Optical Fiber Connector Handbook

1 OPTICAL FIBER WhiCONNECTORt HANDBOOKe Paper JUL 2017

Bernard Lee Tom Mamiya 2 OPTICAL FIBER CONNECTOR HANDBOOK 3 OPTICAL FIBER CONNECTOR HANDBOOK

Optical Fiber Connector Handbook

Contents 6 Introduction to SENKO 7 Basic of Optical Fiber 7 Introduction to Optical Fiber 7 Optical Fiber Connectivity 8 Fiber Optic Connectors 8 Basics of Fiber Optic Connectors 9 Fiber Optic Connector Assembly 12 Connector Assurance (GR-326-CORE) 14 Service Life Test 16 Extended Service Life Test 17 Random Mating Loss Performance 18 Connector Testing 18 Insertion Loss 20 Return Loss 22 Introduction to Test Equipment 22 Power Meter & Light Source 22 Limitations 22 Optical Time Domain-based Measurement (OTDR) 23 Limitations 23 Backscatter Coefficient Settings 23 Index of Refraction (IOR) 23 Mode Field Diameter (MFD) Mismatch 24 Dead Zone 24 Helix Factor 4 OPTICAL FIBER CONNECTOR HANDBOOK

Optical Fiber Connector Handbook

Contents 25 Optical Continuous Wave Reflectometer (OCWR) 25 Limitations 26 Testing Procedure 26 Insertion Loss Measurement with Power Meter & Light Source 26 Cut-back Method 26 Substitution Method 27 Insertion Method 27 Insertion Loss Measurement with OTDR 28 Return Loss Measurement with OTDR 29 Return Loss Measurement with OCWR 30 Connector Hygiene 30 Overview 31 Optical Connector Ferrule & Contamination 32 Inspection Standards 34 Inspection Tools 35 Inspection Tools for MPO Connectors 36 Cleaning Tools 38 Cleaning Challenges for MPO Connectors 39 IEC Connector Type 39.1 IEC 61754-2 BOFC Connector 39.2 IEC 61754-3 LSA Connector 39.3 IEC 61754-4 SC Connector 39.4 IEC 61754-5 MT Connector 39.5 IEC 61754-6 MU Connector 39.6 IEC 61754-7 MPO Connector 5 OPTICAL FIBER CONNECTOR HANDBOOK

Optical Fiber Connector Handbook

Contents 39.7 IEC 61754-8 CF08 Connector 39.8 IEC 61754-9 DS Connector 39.9 IEC 61754-10 Mini MPO Connector 39.10 IEC 61754-12 FS Connector 39.11 IEC 61754-13 FC Connector 39.12 IEC 61754-15 LSH Connector 39.13 IEC 61754-16 PN Connector 39.14 IEC 61754-18 MT-RJ Connector 39.15 IEC 61754-19 SG Connector 39.16 IEC 61754-20 LC Connector 39.17 IEC 61754-21 SMI Connector 39.18 IEC 61754-22 F-SMA Connector 39.19 IEC 61754-23 LX.5 Connector 39.20 IEC 61754-24 SC-RJ Connector 39.21 IEC 61754-25 RAO Connector 39.22 IEC 61754-26 SF Connector 39.23 IEC 61754-27 M12 Connector 39.24 IEC 61754-28 LF3 Connector 39.25 IEC 61754-29 BLINK Connector 39.26 IEC 61754-30 CLIK! Connector 39.27 IEC 61754-31 N-FO Connector 39.28 IEC 61754-32 DiaLINK Connector 39.29 IEC 61754-34 URM Connector 61 Biography 6 OPTICAL FIBER CONNECTOR HANDBOOK

Introduction to SENKO

SENKO Advanced Components is a wholly owned subsidiary of the SENKO Group, which is headquartered in Yokkaichi, Japan. From its humble beginnings in 1946, the SENKO Group currently has an estimated annual revenue of $1.4 billion globally. SENKO Advanced Components itself has 14 offices and dozens of design and manufacturing facilities providing local support to customers all around the globe.

SENKO Advanced Components develops, manufactures, markets and distributes over 1000 fiber optic products for the telecom & datacom industries worldwide.

SENKO Advanced Components was incorporated in the United States in the early nineties and has since being recognized as one of the industry’s specialists in passive fiber optics interconnect and optical components.

An ISO-9001 approved company, SENKO is able to provide multinational corporations with the technical expertise to liaise with engineers, and the manufacturing flexibility to develop custom products for the ever growing high tech industry.

Many of our products were created to resolve a specific design challenge faced by our customers. We offer one of the industry’s largest product portfolios, and our quality is second to none.

Our mission is to be the best global provider of passive fiber optic components. We strive to provide an extensive portfolio of high quality products and services, available on a global scale, with excellent delivery time. We will stand by products, providing our customers with superior post-sales support.

Our customers, suppliers and partners are essential to our success, and shall be treated with respect and integrity. Our team is committed to understanding the technical requirements and service expectations of our customers, and share the goal of resolving the specific challenges these clients face in their own business. 7 OPTICAL FIBER CONNECTOR HANDBOOK

Basics of Optical Fiber

Introduction to Optical Fiber

The use and demand for optical fiber networks has experienced Wireless exponential grown over the past years. Optical fiber networks are widely deployed for various applications ranging from global telecommunications, signaling to desktop computers. These includes Telco/FTTx Data Centers the transmission of voice, data and video over short distances of meters to hundreds of kilometers across continents. Optical fiber is also used in systems for reliable and secure Silicon Photonics/ transmission of data and financial information between computer On-Board Optics terminals, companies and countries around the world. Cable television Security companies also use optical fiber to deliver data services and digital video content to consumers. With the introduction of online video streaming and higher definition video such as the 4K format and Medical Fiber Optic the upcoming 8K format, optical fiber is required to deliver higher bandwidth connectivity. Optical fiber also enables new technology, application and services such as remote learning and tele-medicine through transmission of digital content and low latency control of remote devices. Other applications for optical fiber includes automation, automotive, industrial, space and military.

Optical Fiber Connectivity

In order to build an optical fiber network, optical connectivity is required to extend, branch or split an optical fiber. There are mainly three methods to terminate an optical fiber, which are fusion splicing, mechanical splicing and optical connectors.

Fusion splicing is the process of welding two optical fibers together. This is usually done by using and electrical arc in a fusion splicer. The ends of the two optical fibers are melted and forms a continuous bond. This method results in the lowest attenuation and reflectance. It also provides the strongest and most reliable joint between two fibers.

Mechanical splicing is the process of jointing two optical fibers through a mechanical splice unit. The mechanical splice is a self-contained unit that has a V-groove which aligns the optical fiber within the unit. The two fibers are butted against each other with some index matching gel to improve the optical transmission. Mechanical splicing is a non-permanent connection.

An optical connector is a termination at the end of an optical fiber that enables a quick and flexible fiber mating and demating compared to splicing. The connectors are mechanically coupled to align the fiber cores. Fiber optic connectors are usually used in situations that require quick fiber termination or increased flexibility such as in cross connection panels and customer premises termination. 8 OPTICAL FIBER CONNECTOR HANDBOOK

Fiber Optic Connectors

Basics of Fiber Optic Connectors

There are many types of optical connectors. Different types of connectors are used depending on the equipment and application. Straight Sleeve Optical connectors have been designed throughout the years either for specific application, improving on existing connector quality or Ferrule Fiber to increase connection density. Optical connection are available for different types of fiber such as glass optical fiber, polymer optical fiber and plastic optical fiber. In addition, connectors are also available for both single mode and multimode networks.

A good connector design is determined by factors such as low Alignment Sleeve coupling loss, interchangeability, ease of assembly, environmental resilience, high reliability, ease of connection, repeatability and low cost of manufacture and operation. There are many different types of connectors which use a variety of techniques for coupling such as bayonet, screw-on, latched and push/pull.

Fiber optic connectors are mostly butt joint type connection where the optical fiber is secured in a precision alignment sleeve called a ferrule. Two connector ferrules are aligned and butted against each other within an adapter to complete the fiber optic connection. There are two commonly used butt-joint alignment designs which are the straight sleeve and tapered sleeve. 9 OPTICAL FIBER CONNECTOR HANDBOOK

Fiber Optic Connector Assembly

There are generally 3 steps in the optical fiber connector assembly which are adhesion, polishing and assembly. In this example, the general method of connectorizing an optical cord is outlined.

Step 1/3 Adhesion

• The connector boot and crimp eyelet is slotted through the fiber cord

• The cord is then stripped to expose the Kevlar and fiber buffer within the cord

• The fiber buffer is then stripped to a certain measurement to expose the optical fiber and cleaned

• A mixture of epoxy is prepared to be used as adhesive for the optical fiber in the ferrule

• The connector ferrule is connected to a pump which sucks the epoxy into the connector ferrule

• The prepared optical fiber is then inserted into the connector ferrule

• The connector ferrule with the optical fiber is then placed in an oven for curing

• After the connector ferrule is cured, excess fiber protruding out of the ferrule is carefully cut

• The connector ferrule is now ready for polishing.

boot, bare buffer

crimp eyelet

connector sub-assembly

connector housing boot, short

fiber ferrule

dust cap 10 OPTICAL FIBER CONNECTOR HANDBOOK

Step 2/3 Polishing

• The prepared connector ferrule is then affixed onto a ferrule holder jig

• The jig is then secured onto a polishing machine above a polishing pad

• Depending on the connector ferrule type and connector polishing requirements, suitable polishing films and

polishing program are chosen

• A piece of polishing film is placed onto the polishing pad. The initial polishing uses a coarse film

• The polishing machine is started. Distilled water is added to help smoothen the polishing

• The polished connector ferrule is then rinsed by using an ultrasonic washer

• The connector ferrule is then polished again by using a finer polishing film and rinsed after finishing

• This step is repeated as many times as required with the suitable polishing film until it is ready for assembly

• After polishing, the ferrule endface is examined by using an interferometer to ensure the prepared ferrule is within

the acceptable tolerances

• If the connector endface ferrule is not within the acceptable limits, the endface ferrule can be re-polished but this

can only be done for a limited number of times before the ferrule is rendered unusable.

After rough polishing After medium polishing

After fine polishing 11 OPTICAL FIBER CONNECTOR HANDBOOK

Step 3/3 assembly

• After the connector ferrule passes the interferometer testing, connector assembly can begin

• The connector ferrule is slotted into the subassembly then few drops of epoxy can be added to the end of the

subassembly where it is to be crimped

• The connector Kevlar is then spread around the end of the subassembly

• The crimp eyelet is then slotted over the Kevlar and subassembly then crimped to secure the cord Kevlar

• The boot is then slotted over the crimp eyelet and pushed toward the subassembly

• The connector housing is then slotted over the subassembly according to the connector orientation

• The connector ferrule is then cleaned and the dust cap is slotted over the connector ferrule to complete the connector

production. 12 OPTICAL FIBER CONNECTOR HANDBOOK

Connector Assurance (GR-326-CORE)

As demand for optical connectors increases globally, so does the supply. When one visits trade shows, one will find numerous suppliers offering from basic components to finished cable assembly products. One key fact that end users have discovered in recent years is ‘not all connectors are equal’. The quality, reliability, and performance of optical components and cable assembly products such as patch cords are assured by selecting the best components and by terminating and polishing with the best equipment and procedures. These components GR 326 and procedures must assure that the jumper assemblies meet or CORE exceed the requirements of all pertinent industry specifications such as the internationally recognized GR-326 standards. This paper describes the relevance of the criteria in the applicable industry specifications, as well as the importance of the physical parameters and how they relate to the performance of the jumper assembly.

GR-326-CORE (Generic Requirements for Singlemode Optical As networks evolve and new products are offered the standards are Connectors and Jumper assemblies) was initially created by Bellcore typically reviewed to see if there are changes that need to be made and continues to evolve as one of the more popular standards in or criteria added. A good example of this was the addition of four the telecommunications industry. Bell Communications Research, wavelength testing (1310nm, 1490nm, 1550nm, 1625nm) in GR-326 Inc. or Bellcore was established in the early 1980’s by the Regional issue 4, this was added because of the heavy use of connectors and Bell Operating Companies (RBOC’S) upon their separation from cable assemblies in FTTH networks. Field data is also a very important AT&T. Bellcore served as the research and development, training part of the process when determining the need for reissues of the and standard setting arm for the RBOC’s. Following a divestiture standard. As some of the current networks have been in service for of the company in 1996, Bellcore was officially renamed Telcordia many years, review of FIT (failure in time) rates along with post mortem Technologies in 1999. In 2012 Telcordia was acquired by Ericsson. investigations provide invaluable data about the components long term reliability. When the standards are developed, there are GR-326-CORE was written as part of Telcordia’s General Requirement many other industry standards that are referenced. Standards from series to be consistent with the Telecommunications Act of 1996 and IEC, TIA/EIA, ASTM, ISO, ITU, UL as well as other Telcordia General it is intended to be the industrial specifications for long haul high- Requirement standards are referenced for test procedures, test speed applications such as telecommunications and cable TV. criteria, intermatebility criteria etc. When these standards are updated, There has been a total of four issues of GR-326, initial release, Issue they need to be reviewed to determine if a GR-326 reissue is needed 2 December 1996, Issue 3 September 1999 and the current Issue 4 to bring them in line. February 2010. The Telcordia views in any particular release are The purpose for GR-326 is to determine a connector or connector developed from the expressed needs of the Telcordia Technical Forum assembly’s ability to perform in various operating conditions, and to (TTF), the TTF is made up from the companies who participated in the determine long term reliability. development of each new issue. 13 OPTICAL FIBER CONNECTOR HANDBOOK

The standard is broken down into 4 main categories as shown in table below:

List of Main Test Categories

These General requirements cover documentation, packaging, General Requirements design features, intermateability, product markings and safety

A sequence of environmental and mechanical tests that Service Life Testing simulate possible conditions the connectors or connector assemblies may be under while in service

Extended Service Life Various tests intended to determine long term reliability of the connector or connector assemblies. Usually a simulated 25 Testing year lifetime

The program focuses on requirements for the manufacturing Reliability Assurance process that relate to long term reliability and performance of the finish product. Also includes additional testing to ensure Program the stability of the manufacturing process

The GR-326-CORE test is one of the most comprehensive testing methodologies which will not only test the product’s material and manufacturing precision but also the quality of workmanship. A full test will take a minimum of 2000hrs with multiple tests running in parallel. As mentioned earlier, the GR-326-CORE test is divided into two main tests (i.e. Service Life Tests & Extended Service Life Tests). In the majority of cases, when a sample is requested, a ‘golden sample’ will be provided which will most definitely pass all tests with flying colors. Hence, one should always ask for a GR-326-CORE compliance certificate which is issued to manufacturers whom has passed the GR-326 compliance test at any accredited 3rd party test laboratory in the world. 14 OPTICAL FIBER CONNECTOR HANDBOOK

Service Life Test

The function of the Service Life test is to simulate the stresses a connector may experience during its lifetime. The test is divided into two sections namely the Environmental Test & Mechanical Tests. The Environmental Tests are NOT ONLY performed to ensure the jumper assemblies will be able to withstand prolonged exposure to 85°C or temperature fluctuations of up to 125°C but also to accelerate the effects of aging on jumper assemblies. Details of each of the test are explained in the following table.

GR-326-CORE Environmental Service Life Test Thermal Aging The Thermal Age Test is considered the least extreme of the environmental tests in terms of stress applied, and is intended to simulate and accelerate the processes that may occur during shipping and storage of the product. Connectors are subjected to a temperate of 85 degrees Celsius with uncontrolled humidity for duration of 7 days, with measurements taken before and after testing.

Thermal Cycle During thermal cycling, the temperature fluctuates over an expansive range, subjecting the product to extreme heat and cold. Thermal cycling involves changing the ambient temperature of the connector by 115 degrees Celsius (75° to -40°) over the course of three hours. Heavy stresses and strains will be applied to each of the materials in the product. This test will also expose any weaknesses in the termination. If the design and procedures are not optimal, this can lead fiber cracks or breakage.

Humidity Aging Humidity aging is designed to introduce moisture into the connector and to determine the effect that the moisture has on the samples. This test is performed at the elevated temperature of 75 degrees Celsius for 7 days, while the connectors are exposed to 95% RH (relative humidity)

Humidity/ Condensation Cycle Humidity/Condensation cycling is performed in order to determine the effect that water has on the connector when a rapid transition in moisture occurs. This can cause water molecules to freeze or evaporate within the connector assemblies, potentially exposing “gaps” in the physical contact between connectors within an adapter. This phenomenon may have previously been masked by the water acting as an optical intermediary. The purpose is to achieve heavy condensation, so as to simulate a worse-case condition that may occur in outside plant applications.

Dry-out Step The product is exposed to a drying step at 75 degrees Celsius for 24 hours before the Post-Condensation Thermal Cycle is performed. The purpose is to remove any moisture that may remain from the previously performed Humidity/Condensation Cycling.

Post Condensation Thermal Cycle This is identical to the Thermal Cycle that was previously performed. The changes that may occur in the connector during Humidity/Condensation cycling are often revealed once the condensation is removed (as is the purpose of the ‘Dry-Out’ step), and these changes can potentially affect the loss and/or reflectance of the connector. 15 OPTICAL FIBER CONNECTOR HANDBOOK

There are several mechanical tests (Figure 6) required to be performed once the aging is complete. These include: Flex Testing, Twist Testing, Proof Testing, Impact Testing, Vibration Testing, Durability, and Transmission with an Applied Load. Again, details of each of the test are explained in Table 3.

Table 3 GR-326-CORE Mechanical Service Life Test

Vibration Test In a vibration test, the products being tested are mounted to a “shaker.” By stressing the connectors in this fashion, the test will reveal whether high frequencies of vibration induce performance change in the connectors being tested. The test is conducted on three axis for two hours per axis at an amplitude of 1.52mm with the frequency sweeping continuously from 10 and 55 Hz at a rate of 45Hz per minute.

Flex Test The purpose of performing the flex test is to simulate stresses on the terminated cable and mated connector that could be incurred over the life of the connector. The boot, in particular, is important in this test, as it serves as one of the main points of strain relief. Thus, if the materials in the boot are inadequate, the boot may not function as intended. In addition, this will confirm that the fiber will not become uncoupled from the connector under such circumstances.

Twist Test The twist test puts a rotational strain on the fiber, which tests the strength by which it is coupled with the connector. In addition, the adequacy of the crimp will also be tested. This, like the flex test, will help to identify weaknesses in the termination process.

Proof Test Proof Testing ensures the strength of the latching mechanism of the connector, as well as the crimp during the termination process. Should the jumper assembly receive a sudden tug after installation, this test ensures that the jumper assembly will neither break nor pull out of the adapter.

TWAL testing will stress the samples by applying different weights at multiple angles. TWAL (Transmission With Applied Load) The series of weights used depends on the media type of the cordage, as well as the form factor. Small Form Factor connectors are subject to a more extensive range of measurements.

*Note: Live measurements are made while the samples are under stress; this is done to reflect any degradation in transmission that might have incurred while the product is stressed in the field.

Impact Test Impact Testing is performed to verify that the connectors are not damaged when they are dropped. A cinderblock is mounted to the bottom of the fixture, approximately 1.5m from the horizontal plane that the connector will be dropped from. The connector contacts the cinderblock, and the process is repeated 8 times.

Durability Test Durability testing is designed to simulate the repeated use of a connector. This test involves repetitively inserting (200 times) the connector into an adapter; this is done at different heights (3 ft., 4.5 ft., and 6ft) so as to simulate what a user in the field might encounter when standing in front of a telecom rack. The test can potentially reveal any problems with the design and/or material flaws in the connector, such as any part of the latching mechanism that may be heavily strained or flawed by frequent use 16 OPTICAL FIBER CONNECTOR HANDBOOK

Extended Service Life Test

The criteria for connector and jumper assembly extended service life testing are exclusive to GR-326-CORE. The testing includes exposure to a variety of environments, including additional Environmental Testing and Exposure Testing. The additional Environmental Tests include extended versions of the Thermal Life, Humidity, and Thermal Cycle. These tests, which run for at least 2000 hours each (83 days), are further studies in the life of the connector across a range of service environments. Testing is non-sequential, so there is no cumulative effect. The Exposure Tests include Dust, Salt Fog, Airborne Contaminants, Ground Water Immersion, and Immersion/Corrosion. During the extended Environmental Testing, many of the extruded compounds used in jacketing and buffering will shrink after exposure to elevated temperatures, which can cause micro bending in the glass fibers and induce excessive loss..

GR-326-CORE Extended Service Life Test

Dust can seriously impair optical performance. Particles that contaminate endface can block optical signals and induce loss. Whether or not the dust particles find an exposed path to a ferrule endface is largely a matter of probability. Over time, dust particles will find their way to the optical connection if it is possible. While the dust particles are not difficult to remove, the cleaning process involves disconnecting the connector, which not only stops the transmission, but also exposes the endface to additional risk of contamination. This test involves intense exposure to a dust of specified size particles in order to determine if there is a risk of any particle finding its way to the ferrule endfaces.

Salt Fog (referred to as Salt Spray) is performed to guarantee the performance of the jumper assembly in free breathing enclosures near the ocean. This test involves exposing the connector to a high concentration of Sodium Chloride (NaCl) over an extended period. After the test, optical testing is performed, followed by a visual inspection to confirm that there is no evidence of corrosion on the materials.

The Airborne Contaminants test is designed to guarantee the performance and material stability of connectors in outdoor applications with high concentrations of pollution. The test repeatedly exposes mated and unmated connectors to various gases and inspects the connector not only optically, but also performing the same visual examination as in the Salt Fog test. An assortment of volatile gases is used in a small chamber for 20 days to simulate prolonged exposure to these elements.

The materials are also verified in the Immersion/Corrosion test. This test has no optical requirements, but instead involves a prolonged submersion in uncontaminated water. This test, like Dust, Salt Fog, and Airborne Contaminants, involves both mated and unmated connectors. Mated connectors are checked for ferrule deformation by measuring the Radius of Curvature before and after the test, and comparing the values. If the ferrule is not geometrically stable during this test, it could be an indication of a flaw in the zirconia material used in the ferrule. Unmated connectors are checked for Fiber Dissolution, which involves checking to see if the fiber core has not recessed too far into the fiber cladding.

The final exposure test is Groundwater Immersion.This test verifies the ability of the product to withstand underground applications. The Immersion/Corrosion test is strictly to verify the materials involved, and uses de-ionized or distilled water. Connectors deployed in underground environments are much more likely to be exposed to contaminated mediums if their enclosures fail. During this test, the connector is exposed to a variety of chemicals found in sewage treatment and agricultural fertilization, among other applications, as well as biological mediums. These chemicals include ammonia, detergent, chlorine, and fuel. Presence of these chemicals can have a detrimental effect on the materials comprising the connector and adapter, reducing optical performance. 17 OPTICAL FIBER CONNECTOR HANDBOOK

Random Mating Loss Performance

The most common optical performance measurement you see tested with a master jumper is what you will be getting in the for an optical connector is the Insertion Loss and Return Loss. actual usage of the product such as in racks, on devices and any other Jumper measurement is usually done at the 1310nm and 1550nm finished product. The IEC 61753-1 standard was introduced to outline wavelength by using a master jumper and a master adapter. This is the Insertion Loss and Return Loss specification based on randomly to guarantee the performance measurement consistency. A master mated connectors. The compliance to this standard guarantees the jumper and master adapter are rare products which have near perfect loss performance of random mated connectors and categorizes it into geometric and loss performance. A master jumper and adapter is 4 grades for Insertion Loss and 4 grades for Return Loss. The difference usually used for factory assurance measurement to maintain product of a good connector and a bad connector can clearly be differentiated performance consistency. As such, the connector and adapter loss be measuring the Insertion Loss of a randomly mated connector. It is performance report from the factory is based on a measurement known that a connector that has a guaranteed IL of 0.5dB against a with a master jumper and adapter. They are usually not used in actual master can increase to as high as 1.00dB or higher in random mating. network deployment due to its high cost and rarity in production. It The tables below outlines the Insertion Loss and Return Loss grades. is commonly misunderstood that the Insertion Loss and Return Loss

Attenuation Attenuation Random Mated Insertion Loss Random Mated Return Loss Grade Grade

Grade A Not Defined Yet Grade 1 ≥ 60 dB (mated) with ≥ 55 dB (unmated)

≤ 0.12 dB mean ≤ 0.25 dB max for > 97% Grade B Grade 2 ≥ 45 dB of samples

≤ 0.25 dB mean ≤ 0.5 dB max for > 97% Grade C Grade 3 ≥ 35 dB of samples

≤ 0.5 dB mean ≤ 1.0 dB max for > 97% Grade D Grade 4 ≥ 28 dB of samples

Insertion Loss data against Master Random mating Insertion Loss

GR 326 IEC IEC IEC IEC IEC Max IL Max IL Grade A Grade B Grade C Grade D (0.4dB) (0.5dB) (0.15dB) (0.25dB) (0.50dB) (1.0dB) 120% 120% Points where Max IL is reached for each connector brand Points where Max IL is reached for each connector brand 100% 100%

80% 80%

SENKO Low Loss 60% 60% SENKO Premium SENKO Standard 40% 40% High quality Competitor

20% 20% Low quality Competitor

0% 0% 18 OPTICAL FIBER CONNECTOR HANDBOOK

Connector Testing

Insertion Loss One of the main advantages of fiber optic networks is the efficient operational wavelength light transmission suited for long distance telecommunications. Optical attenuation occurs when the light intensity reduces as light propagates through an optical network. Optical attenuation which is also known as Insertion Loss (IL) reduces the potential transmission distance of an optical network. Although this can be compensated by the use of higher power The largest contributor of attenuation in an optical network are optics, this will introduce a higher deployment cost. In addition, the interconnect components such as connectors and splitters. The use of high power optics can introduce new set of problems such as degradation of light intensity is managed through the precise increased thermal stress on the optical network, thermal lensing, non- engineering, manufacturing, quality control and long term reliability linear attenuation, and increased requirement for optical hygiene. of optical fibers and the interconnect components. The IEC 61300- Insertion Loss is defined as the ratio of the optical input power over 3 family of standards outline the basic test and measurement the optical input power. A representation of IL in decibels (dB) is procedures for fiber optic interconnecting devices and passive shown below: components.

Optical connectors is one of the largest contributors of attenuation. Insertion Loss (IL) = Fiber optic connectors are an integral part of an optical network to enable a point of flexibility to alter the network connectivity such as a cross-connect rack in an exchange. A fiber optic connection is -10 log (P /P ) made up of two connectors which are plugged into an adapter which 10 o in aligns the connector ferrules within its sleeves. Attenuation from connectors arise from multiple factors such as connector cleanliness,

where: Po = Output Power Pin = Input Power connection gap, core centricity error, angular misalignment and lateral misalignment. 19 OPTICAL FIBER CONNECTOR HANDBOOK

Example of a perfect connector termination

• Clean connector endface • Straight joint with good lateral and angular alignment • Fiber core is aligned and in contac

Example of contaminated connector endface contamination

• Contamination on the fiber core can cause high attenuation and even permanent damage if the contamination is burnt by high optical power • Contamination in between two connectors can cause a gap • An air gap between the connectors can result in a lower return loss. connector gap

Example of connector with angular misalignment

Angular misalignment can be caused by:

• Low quality barrel in the bulkhead adapter or connector ferrule • Contamination on the side of the ferrule

Example of connector with lateral misalignment

Lateral misalignment can be caused by:

• Low quality barrel in the bulkhead adapter or connector ferrule • Contamination on the side of the ferrule

Example of core concentricity error Actual position of fiber core • Position of the fiber core is offset from the actual Central position of fiber core center of the connector ferrule • Note: Image is an exaggeration of a core off-set

Core Concentricity Error 20 OPTICAL FIBER CONNECTOR HANDBOOK

Return Loss

To ensure the proper performance of an optical transmission system, various parameters such as attenuation and Optical Return Loss (ORL) must be within the acceptable tolerance level of the transmission and receiving equipment. ORL is measured based on components such as cables, patch cords, pigtails and connectors as well as an end-to-end network ORL level. With increasing data speeds and the use of WDM technology, the In addition to the increase in network attenuation, high levels of measurement of ORL is becoming more important in characterizing reflected optical power can cause light-source signal interference, optical networks. ORL is defined as the ratio of light reflected back higher Bit-Error Rate (BER) in digital systems, lower Signal to Noise from an element in a device, to the light launched into that element. Ratio (SNR), laser output power fluctuations and in more severe This is usually represented as a negative number in decibels (dB). The situations, permanent damage to the laser source. ORL and reflectance mathematical formula representing ORL is as shown below: must be measured on a component level, such as connector and cable assembly, and an end-to-end network level. Higher transmission bandwidth networks requires higher ORL performance. For example, an OC-48 2.5Gbps transmission network has a minimum ORL level of 24dB while an OC-768 40Gbps has a minimum ORL level of 30dB. An FTTx network delivering video Return Loss (RL) = content with a low BER tolerance has a minimum ORL level of 32dB.

As outlined in the IEC 61300-3-6 standard, there are mainly 4 methods to measure return loss which are: -10 log (P /P ) 10 r in • Optical Continuous Wave Reflectometer (OCWR)

• Optical Time Domain Reflectometer (OTDR)

where: P = Reflected Power P = Input Power r in • Optical Low Coherence Reflectometry (OLCR)

• Optical Frequency Domain Reflectometry (OFDR) 21 OPTICAL FIBER CONNECTOR HANDBOOK

Causes of Optical Return Loss

The measurement methods are applied depending on the Device under Test (DUT) condition, level of return loss, measurement distance and the measurement resolution. This paper will focus on the return loss measurement using the OCWR and OTDR methods. Back reflectance is described as the ratio of reflected optical power to the incident optical power at the input of the device. The term ORL is used to describe the ratio of relative magnitude of the cumulated back reflectance or multiple Fresnel events and backscattered signal power to the optical power at the input of the device. There are mainly two factors that cause ORL which are Fresnel backreflection and Rayleigh backscattering.

Fresnel backreflection is caused by different network elements where a transition through different mediums occur. Optical connectors are usually the highest contributors of reflections due light air gap attenuated light to air gaps, impurities, geometry misalignments, and manufacturing imperfections. Common sources of Fresnel backreflection are optical connectors, mechanical splices, open fiber ends and cracks in the optical fiber. Significant light is backreflected to the source when light travels from the fiber core to air. In ORL sensitive networks, Angle-Polished Connectors (APC) are usually deployed to reduce backreflection to the source. reflected light

Rayleigh backscattering is an intrinsic property of optical fiber which causes light to scatter. This is usually caused by defects and impurities introduced into the fiber core during the manufacturing process, or light Rayleigh scattering regions of mechanical stress such as microbending. A fraction of the scattered light which is directed back to the source is detected as ORL while the majority of scattered light will be lost. Rayleigh scattering occurs along the total length of fiber.

reflected light 22 OPTICAL FIBER CONNECTOR HANDBOOK

Introduction to Test Equipment

Power Meter & Light Source

The Power Meter and Light Source works as a pair of devices. As the name suggests, the Light Source is a device that injects a certain amount of light into the DUT while the Power Meter detects the light power level that comes out of the other end of the DUT. The difference in the power level provides an accurate representation of the DUT insertion loss.

Limitations

Unlike the OTDR, the Power Meter & Light Source testing method is unable to discern the individual elements within the DUT. This testing method can only give the total insertion loss of the DUT. Depending on the connector quality, the act of mating and demating a connector can result in a different insertion loss level. When measuring a low attenuation DUT, the connector loss variable can significantly distort the actual insertion loss reading. This limitation can be overcome by using a method called the cut-back method which maintains the connector termination to the Light Source and Power Meter but it introduces a fusion splicing which is a new loss element, which has a very low attenuation level if done properly, that is not part of the DUT.

Optical Time Domain–Based Measurement (OTDR)

Optical time domain–based measurement spatially evaluates backreflection characteristics both in individual components and along the length of a fiber. One main instrument that uses this measurement method is the optical time-domain reflectometer (OTDR). An OTDR measures the backscatter level of the fiber medium itself and the peak reflection level of Fresnel events along an optical link. The backscatter measurement level is a function of the fiber backscatter coefficient—an intrinsic factor of the fiber under test—and the pulse width used for measurement. As its name suggests, an OTDR operates in the time domain and measures the backscatter optical-power level from the fiber itself. It enables users to measure Fresnel backreflection at any point along the fiber under test without de-mating optical interconnections. A light pulse is introduced into an optical link and will experience both backreflection and Fresnel events along the pathway. The power level of light reflected back to the source is measured with reference to the time it takes for the light to return to the source. In this way, the OTDR estimates the distance of an event from the source according to the elapsed time versus the speed of light. This makes the OTDR a very useful tool in evaluating the distance of the optical network under test as well as the location of components in the network, thus enabling the tester to evaluate the network for commissioning purposes and locate network faults for maintenance. There are two types of OTDRs: the photon-counting OTDR (PC-OTDR) and the network OTDR. Although both types of OTDR use the same principles to measure ORL, the PC-OTDR applies a much shorter optical pulse width, enabling a much higher spatial resolution and reflection sensitivity. However, this reduced dynamic range lowers the maximum useful DUT length of a PC-ODTR. Due to these differences, the two types are applied for different purposes: network OTDRs are typically portable and usually deployed in outside plant networks for commissioning and troubleshooting, while PC-OTDRs are usually used for qualification and troubleshooting of individual components, modules, or subsystems in which reflections are often closely spaced.

Reflectance Max Spatial Reflection Optical Pulse Max Length of Measurement Resolution Sensitivity Length DUT Range Network > 1 m −60 dB ≈ 50 dB ≥ 10 ns < 100 km OTDR

PC-OTDR ≈ 10 mm < −120 dB ≈ 60 dB ≤ 10 ns < 200 m 23 OPTICAL FIBER CONNECTOR HANDBOOK

Limitations

Backscatter Coefficient Settings As OTDRs measure backreflection power levels, the reflectance of a given element in the DUT depends on the fiber backscatter coefficient, optical pulse width, and the measured reflectance amplitude with reference to the backscatter level. An inaccurate backscatter coefficient value setting can lead to an error in measuring reflection level. The percentage of measurement uncertainty increases with a lower reflectance value. The backscatter coefficient is usually one of the parameters that is set when performing an OTDR measurement. In a fiber-access network, especially one that has legacy fibers, there may be a combination of various fiber standards – for example from early G652.A fiber to G657.A2 fiber – as well as fiber from different suppliers manufactured with different methods, such as the plasma chemical vapor deposition (PCVD) method or the modified chemical vapor deposition (MCVD) process. The OTDR’s backscatter coefficient setting cannot be adjusted to match the varying fiber characteristics in the network under test.

Index of Refraction (IOR) IOR is a way to measure the speed of light in a medium with reference to the speed of light in a vacuum, where light moves fastest. Light travels at approximately 3 x 108 ms−1 in a vacuum. The IOR of a medium such as an optical fiber core is calculated by dividing the speed of light in a vacuum by the speed of light in the medium. By definition, the IOR of light in a vacuum is denoted by 1. A typical single-mode fiber has a silica- doped core with an IOR of approximately 1.447. The larger a medium’s IOR value, the more slowly light travels in that medium. An inaccurate IOR setting in an OTDR will cause the total distance of the network measured to be skewed. If the IOR is set too high, the OTDR will calculate the network distance to be shorter than it actually is; likewise, if the IOR is set too low, the OTDR will measure too long a distance. A difference in IOR setting of just 0.01 can cause a reading difference of 70 m over a 10 km fiber span. When an OTDR is used to locate a specific fault in a network, an incorrect IOR setting can cause the fault location shown in the OTDR to be far off from the actual location.

Mode Field Diameter (MFD) Mismatch The MFD of an optical fiber is the area where light propagates. This area is usually slightly larger than the fiber core as a portion of Backreflection reduced after splice point due to MFD mismatch light propagates through the cladding as well. When two optical core cladding core cladding fibers with different fiber core size and MFD size are spliced, the attenuation measurement by using an OTDR can result in a gainer or an exaggerated loss. This is due to the propagation of light through mediums with different Index of Reflection. The attenuation reading from the OTDR depends on the difference in fiber MFD and the measurement direction of the OTDR. If the OTDR measurement is made from a fiber with a larger MFD to a fiber OTDR measurement results in an exaggerated loss with a smaller MFD, the reading will result in a gainer. However, if the measurement is made from a fiber with a smaller MFD to a fiber with Backreflection increased at splice point due to MFD mismatch a larger MFD, the reading will result in an exaggerated loss. core cladding core cladding

OTDR measurement results in a gainer 24 OPTICAL FIBER CONNECTOR HANDBOOK

Dead Zone A dead zone is the location of a section of network beyond a reflective event, where subsequent network characteristics cannot be measured. There are two types of dead Attenuation deadzone definition Applies to non-saturating zones: attenuation dead zones (ADZs) and event dead zones (EDZs). peak (good UPC connector) An ADZ is the minimum distance required to make an attenuation measurement for an event. This value is usually defined as the distance between the rising edge of a reflective event to the 0.5 dB deviation from a straight line fit to the optical backscatter 0.5 dB deviation from level. The optical backscatter level is the sloping line that indicates the fiber attenuation straight line backscatter over distance. An EDZ is the minimum distance required for the OTDR to detect two separate events. ADZ This is usually defined as the distance between two cursor points set at 1.5 dB below a reflective peak, where the peak is non-saturating. Dead zone measurement depends on the pulse width and the network element Event deadzone definition Applies to non-saturating peak reflectance level. A shorter pulse width will result in a shorter dead zone, while a (good UPC connector) connector with a high return loss will result in a longer dead zone. When testing a long- 1.5 dB below peak distance network, testers will use a higher pulse width, thus increasing the length of the dead zone. This can cause multiple nearby events to be identified as a single merged event. Examples include the connector and splice of a pigtail as well as both connector ends of a patch cord. EDZ Most OTDR manufacturers specify the OTDR dead zone for the shortest pulse width and optimal connector reflectance. However, this specification cannot be taken at face value. The suitable pulse width to be used for network measurement usually depends on the total length of the network, while individual components within the network Attenuation deadzones of two concatenated connectors have variable reflectance performance due to manufacturing quality and hygiene.

Helix Factor OTDRs are widely deployed in testing and measurement of outside-plant optical fiber networks. In an outside-plant environment, optical fibers are deployed in cables. The most common cable types deployed are loose-tube cables and slotted-core cables. ADZ-1 ADZ-1 Optical fibers within these cables are not strung in a straight line but spiral around a Can’t measure Okay central strength member in an “SZ” fashion within loose tubes. As light from an OTDR travels through the optical fiber, OTDRs measure the optical fiber distance rather than the cable distance. Depending on the helix factor of a cable— Attenuation deadzones of two which can range from 0.3% to 42%, depending on the cable design—a cable 700 m concatenated connectors long may comprise 1,000 m of fiber distance. Without an accurate measurement of the helix factor, fault locating by using an OTDR may result in considerable discrepancy. Most modern OTDRs have a helix setting to adjust the distance measurement.

ADZ-1 ADZ-1 Can’t measure Okay 25 OPTICAL FIBER CONNECTOR HANDBOOK

Optical Continuous Wave-Based Measurement (OCWR)

OCWR relies on a basic power-meter measurement of the launch power (assuming no DUT) as a base reference and compares this to the optical power reflected back to the source. For a backreflection meter, this method is usually used to measure the ORL of patch cords. For an Optical Line Test Set (OLTS), this method can be used to measure the total ORL and attenuation of a network.

Limitations

The OCWR method cannot differentiate between Rayleigh backscatter and Fresnel backreflection. If a patch cord tested with a backreflection meter yields a low ORL result, it is highly likely that the connector is faulty—although there is a possibility that the cord itself has been manufactured with microbends. When using test instruments that employ the OCWR method, the network or component under test must be isolated from the rest of the optical network to prevent any backscatter or reflection from events further down the link. This means that the OCWR method cannot be deployed on a live network. To isolate the DUT from unwanted reflections, the optical fiber must be terminated at two different points. The two commonly used termination methods are the mandrel wrap and the index-matching gel or block. Each of these methods have limitations, as shown in the table below. The difference in backreflection between the two termination points is calculated to give the DUT backreflection level.

Mandrel Wrap Index-Matching Gel Index Matching Block

Not suitable for connectors with guide pins, Not applicable to non-bendable structures Matching gel might leave a residue on the such as MPOs, or where the connector end- such as hardened cables or cords polished connector end face face is not accessible, such as E2000.

Bend-insensitive fiber does not exhibit Backscatter of the fiber length between the reflective event bend loss and the far end of the cable might amplify reflections

Cannot optically isolate far end Limited effectiveness in terminating reflections through bending.

Manual process to isolate far end and highly depends on the technician’s skill level

Multimode fiber cannot be terminated effectively using mandrel wraps, as the wraps can introduce bend loss but not totally terminate the fiber. In most cases, the use of an index-matching gel or block is the only solution. An index-matching gel or block matches the IOR of fiber, which causes light to diffuse out of the fiber core rather than experience Fresnel backreflection. However, index-matching gels are not as effective as mandrel wraps, and they can never fully prevent backreflection. Multiple measurements are usually required, with the highest return loss measurement result taken as an approximation of the potential result if a mandrel wrap is used. 26 OPTICAL FIBER CONNECTOR HANDBOOK

Testing Procedure

Insertion Loss Measurement with Power Meter & Light Source

Cut-back Method In the cut-back method is the most accurate insertion loss measurement for a Device under Test (DUT). This method is usually used for component testing in a lab situation. The DUT is connected to a light source with a temporary joint which is usually an optical splice. The output of the DUT is then connected to a power meter. The power level measurement is noted as P1. The temporary joint is cut and then spliced to the fiber connected to the power meter. The power level measurement is noted as P0. The optical attenuation of the DUT can then be calculated as P0 – P1.

Light Source Power Meter Temporary joint DUT

Temporary joint

Substitution Method

The substitution method is usually used for component testing where the input and output of the DUT are connectorised. The DUT is connected to a light source by terminating the DUT input connector to a reference adapter. Similarly, the output of the DUT terminated to a power meter by using a reference adapter. The power level measurement is noted as P1. The input and output connectors of the DUT are disconnected and substituted by a patch cord. To achieve a higher DUT attenuation measurement accuracy, a master patch cord with low loss connectors can be used. The power level measurement is noted as P0. The optical attenuation of the DUT can then be calculated as P0 – P1.

Light Source Power Meter Temporary joint

Temporary joint DUT 27 OPTICAL FIBER CONNECTOR HANDBOOK

Insertion Method

The insertion method is usually used to measure a connection attenuation performance such as a splice point, or a field-mountable connector. The light source and power meter is directly connected and the power level measurement is noted as P0. The connection between the light source and the power meter is then cut. The cut fiber is then spliced to re-establish the optical network with a higher attenuation which is measured and noted as P1. The optical attenuation of the DUT, which in this scenario is a splice point, can then be calculated as P0 – P1.

Light Source Power Meter Temporary joint

Temporary joint Splice or Connector

Insertion Loss Measurement with OTDR

An OTDR is not an ideal equipment to measure optical attenuation as it only detects back reflection level at different locations in the optical network instead of measuring the actual optical output power with respect to the input power. As outlined in a previous section, if two fibers with different specification are spliced, the MFD mismatch may cause a skewed attenuation reading called a gainer and exaggerated loss. The gainer and exaggerated loss reading can be corrected by performing a bidirectional OTDR test and getting the average attenuation reading of the splice event.

Excessive Loss IL Insertion Loss = a a + b

Gainer 2

b 28 OPTICAL FIBER CONNECTOR HANDBOOK

5.4.2. Return Loss Measurement with OTDR Return Loss Measurement with OTDR

A launch lead, which is a standard patch cord with suitable connectors Launch Lead on both ends, must be used to connect the OTDR to the DUT. This OTDR DUT ensures that the first event in the DUT can be quantified. If a launch lead is not used, the high reflection from the OTDR internal connector masks the actual reflectance and attenuation of the DUT.

The correct parameters suitable for the measurement of the DUT is If the optical network parameters are not know, most modern OTDR set in the OTDR. These parameters include the IOR, backscatter, helix have auto settings. The OTDR tests the network starting with a short factor, pulse width, measurement distance, and acquisition time. The pulse width and incrementally increases the pulse width until it importance of an accurate IOR, backscatter and helix factor settings detects an end-of-fiber reading. The OTDR automatically adjusts the is outlined in the previous section. Other important settings are:: pulse width and measurement distance setting which best suits the DUT conditions. • Pulse width: Smaller pulse width has a higher measurement An OTDR trace will be produced to indicate the detected events in the resolution but has limited distance and vice versa. DUT. There may be discrepancies between the OTDR trace result and the actual components in the DUT, this may be due to: • Measurement distance: To be set as closest to the actual network • High quality connectors with low reflectance is recognized as a distance. If set to be lower, the far end of the network is not tested. splice rather than a connector. If set to be too high, the resolution of the network under test will • Undetected events such as low attenuation splices. be low. In PON systems where splitters are installed in the OSP, the use of a short pulse width, such as a 5ns pulse width, will not be able produce • Acquisition time: Test result with low acquisition time will result a readable result after the splitter due to the high loss. A 1:16 splitter in higher noise level. However, longer acquisition time will require will cause about a 14dB attenuation. This will usually cause the OTDR longer man hours for testing purposes trace to drop below the OTDR noise floor. However, using a larger pulse width such as 275ns will cause result in a lower resolution reading before the splitter, thus potentially missing events or merging closely spaced events.

Connector Receive End Launch Lead Splice OTDR

One possible method to test such a network is by using a short pulse splitter to the end of the network. Further tests may be required if the width, such as 5ns to 10ns, to identify all event locations up to the dynamic range is insufficient to get a noise-floor margin of at least splitter. A second test is performed by using a medium pulse width, 6dB. Information from the multiple OTDR traces must be analyzed such as 50ns to 100ns, for increased dynamic range to measure splitter and tabulated into a report. Such testing requires skill and time. In loss while maintaining good resolution. The third test is performed addition, tests are usually performed using the 1310nm and 1550nm by a longer pulse width, such as 275ns or higher, to test past the wavelength to detect macrobends, which results in longer test times. 29 OPTICAL FIBER CONNECTOR HANDBOOK

Return Loss Measurement with OCWR

A reference patch cord is terminated to the light source of the OCWR. The end of the reference patch cord is coiled around a mandrel to ORL A increase attenuation and prevent Fresnel backreflection from the open end connector from being detected. The mandrel is applied as Mandrel close to the end connector as possible. The detected ORL is set as a Reference Patch Cord base reference. OCWR

A DUT is then connected to the reference patch cord. The DUT is ORL A then coiled around a mandrel as close to the connection point as possible. This reduces the optical fiber backscatter from affecting the connector reflectance reading. The OCWR displays the ORL of the DUT with respect to the base reference value. ORL B A master patch cord is usually used as the reference patch cord. A Mandrel master patch cord is manufactured with very strict quality standards Reference Patch Cord to ensure repeatability of measurement result regardless of the test Patch Cord under test OCWR equipment type, manufacturer, the operator or the period of test. The connector interface of the master patch cord has near perfect ORL B specification on the end face radius of curvature, apex offset and fiber protrusion/undercut. ORL of Patch Cord under test = ORL B - ORL A

DUT

FC/APC BR = -58.0db

BR POWER I (LOCAL)

1310 BR0 DARK 1490 Backreflection Meter 1550 O Measurement 1625 Jumper

DUT Termination Termination Point Point

for BRTOTAL for BR0 BRDUT 30 OPTICAL FIBER CONNECTOR HANDBOOK

Connector Hygiene

Overview One of the drivers of many network operators to deploy optical In the past, connector contamination in optical transport networks fiber has been, of course, its performance & reliability. Although or data center fiber interconnect networks were less prevalent due to the general maintenance requirement is greatly reduced, many the controlled environment of exchanges or data centers. However, network operators around the world is finding one main component with the increasing deployment of optical fiber outside plant in an optical fiber network to be the cause of network failures. networks, optical connectors are widely used in outdoor enclosures That component is the optical connector, the ‘weakest link’ of your such as roadside cabinets and pedestals as well as in customer network. Based on a study conducted by NTT Advanced Technology, premise termination points that do not have filters to reduce dust 4 of the top 5 causes of network faults are connector related and the contamination or environment control systems to reduce humidity. No.1 cause is contaminated connector end faces. The same problem Although connector contamination is common, it can be easily is reported by major optical fiber network operators in Asia with the rectified. The main area of an optical connector that must be cleaned lack of appreciation for fiber cleanliness accounting for 90% of all is the ferrule endface. reported faults.

! Connector End Face contamination is the N°1 cause of network faults

1st Contamination of the connector End Face

2nd Poor polishing of the ferrule

3rd Mistakes attaching lables to the cable

4th Damage of the optical connector

5th Damage of the ferrule End Face 31 OPTICAL FIBER CONNECTOR HANDBOOK

Optical Connector Ferrule & Contamination

The ferrule is the most essential part of the connector which holds and centers the optical fiber for connection with another section of a fiber network. As defined in IEC 61300-3-35, an optical connector Clean connection end face is separated into three zones which are the Core (Zone A) where light travels, Cladding (Zone B) which is the outer section of the Core which reflects light back into the Core, and the Buffer Coating (Zone C) which protects the optical fiber from moisture or damage from external forces.

The core of a single mode connector is only 9µm. A piece of dirt, speck of dust or oil smudge in the right position may cause high reflection, insertion loss and fiber damage. Connector cleanliness is Dirty connection critical in high power transmission systems such as DWDM systems or long haul transmission where Raman amplifiers are used, the optical signal transmission power may be up 1W to 5W. In a single mode fiber transmission, such high power transmission may burn the contaminant and fuse the dirt with the silica material of the optical fiber, thus requiring the replacement of the connector.

The source of contamination is usually due to connector mishandling and a lack of understanding for optical hygiene. Some of the most common mistake for contaminating optical connectors are:

• Leaving a connector uncapped for even a short period of time where it will be prone to dust contamination.

• Touching the connector end face with fingers thus leaving skin oil or passing on dirt

• Using unsuitable cleaning methods or products such as toilet paper, water or even shirt sleeves

• Assuming that connectors which are protected by dust caps are clean or factory guarantee cleaned

• Not cleaning both connector end faces before making a connection.

Image above: example of bad practice 32 OPTICAL FIBER CONNECTOR HANDBOOK

Inspection Standards

The ‘IEC-61300-3-35: Fiber optic interconnecting devices and passive components - Basic test and measurement procedures - Part 3-35: Fiber microscope Examinations and measurements - Visual inspection of fiber optic connectors and fiber-stub transceivers’ sets the standards on measurement methods, procedure to assess the connector end face and determines the threshold for allowable surface defects such as scratches, pits and debris which may affect optical performance and it is the de facto standard for the fiber optics industry globally. According to the standards document, there are three inspection methods which are the:

• Direct view optical microscopy

• Video microscopy Fiber Inspection Probe (FIP) • Automated analysis microscopy

The Direct view optical microscopy is essentially a microscope designed to view optical connector end faces. Although most of such microscopes have an optical filter to prevent eye damage from exposure to transmission lasers, many network operators do not approve its use due to health and safety reasons. Another disadvantage of this method is different microscopes need to be used for inspecting a connector or a connector terminated onto a bulkhead adapter.

Video microscopy uses an optical microscope which projects an Automated analysis microscopy image onto a display screen thus preventing any direct exposure to transmitting lasers. An example of a video microscopy is a Fiber Inspection Probe (FIP) with a display unit. Most FIPs available in the market have interchangeable tips to inspect bare connectors or when it is terminated onto a bulkhead adapter. There are also tips available for different connector types.

The Automated analysis microscopy is similar to the video microscopy but with an added feature which uses an algorithmic process to automatically analyze the connector hygiene based on a set criteria. This analysis provides a “Pass” or “Fail” result, thus removing any human assessment ambiguity. 33 OPTICAL FIBER CONNECTOR HANDBOOK

There are two assessment procedures outlined in IEC-61300-3-35 for a single fiber ferrule such as an SC or LC connector and for a multi-fiber rectangular ferrule such as the MPO connector. The end face of the connectors are divided into measurement regions starting from the center of the core and moving outwards.The tables below outline the measurement regions:

Measurement regions for Measurement region for single fiber connector multi-fiber rectangular connector

A B C D

Zone Diameter for single mode Diameter for multimode Zone Diameter for single mode Diameter for multimode

A: Core 0 µm to 25 µm 0 µm to 65 µm A: Core 0 µm to 25 µm 0 µm to 65 µm

B: Cladding 25 µm to 120 µm 65 µm to 120 µm B: Cladding 25 µm to 115 µm 65 µm to 115 µm C: Adhesive 120 µm to 130 µm 120 µm to 130 µm Note 1: All data above assumes a 125 µm cladding diameter. Note 2: Multimode core zone diameter is set at 65 µm to accommodate all common core sizes in a practical manner. Note 3: A defect is defined as existing entirely within the inner-most zone which it touches. D: Contact 130 µm to 250 µm 130 µm to 250 µm Note 4: Criteria should be applied to all fibers in the array for functionality of any fibers in the array.

Note 1: All data above assumes a 125 µm cladding diameter. Note 2: Multimode core zone diameter is set at 65 µm to accommodate all common core sizes in a practical manner. Note 3: A defect is defined as existing entirely within the inner-most zone which it touches.

The IEC-61300-3-35 standard outlines the Pass/Fail threshold level for the visual requirements for the different connector types. These criteria are designed to guarantee a common level of connector condition for connector performance level measurement. Based on the zones of a connector, the standard outlines the allowable number of scratches as well as the size and number of defects. There are four main requirements outlined which are:

• Visual requirements for PC polished connectors, single mode fiber, RL≥ 45dB

• Visual requirements for angle polished connectors (APC), single mode fiber

• Visual requirements for PC polished connectors, single mode fiber, RL≥ 26dB

• Visual requirements for PC polished connectors, multimode fibers

The table below outlines the visual requirements for a single mode angle polished connector:

Zone Scratches Defects

A: Core ≤ 4 None

B: Cladding No limit No limit < 2 µm / 5 from 2 µm to 5 µm / None > 5 µm

C: Adhesive No limit No limit

D: Contact No limit None ≥ 10 µm 34 OPTICAL FIBER CONNECTOR HANDBOOK

Inspection Tools

The race to deploy broadband FTTx networks is resulting in a global To cater for the massive adoption of FTTH services, the cost of fiber technician skill shortage. It is easy to train a technician to perform setting up all the field technician is highly expensive especially with a connector hygiene test but experience in operating and maintaining the various tools and equipment required to perform their tasks a fiber network is required to be able to make correct assessments. effectively. The common connector hygiene inspection tool consists The use of automated techniques de-skill and reduce the risk of poor of an FIP and a monitor to view the connector end face. The monitor installation. An automatic Pass/Fail analysis function based on the may be a standalone unit for the FIP, a different test equipment with IEC-61300-3-35. In addition, Geo tagging features together with cloud a monitor such as an Optical Time Domain Reflectometer (OTDR) or a storage allow centralized review by fewer highly skilled technicians laptop. The high cost of these equipment becomes a barrier to entry and confirmation that procedures were correctly carried out: for many fiber technicians or contracting companies and in many cases, proper inspection is not conducted. Hence, a low cost and high • Prevent any error with a standardized and performance alternative is needed to cater for the market. impartial assessment The cost effective SENKO Smart Probe is one of these cost effective alternative which allows relatively low skilled technicians to inspect • Increase productivity by speeding up the the fiber end faces and stream the images to any laptop, tablet or assessment process through set algorithm smartphone. Many technicians already carry smartphones or tablets as part of their daily operations hence no additional display device is required and the SENKO Smart Probe connect to the smart devices via • Avoid replacement of connectors with slight conventional Wi-Fi. defects that do not adversely affect performance

In order to keep a record of connector inspection, all test results can be • Ensuring excellent long term connectivity uploaded into a cloud repository for future references or for reporting performance purposes. These uploaded records with their associated location data give skilled technicians the opportunity to review the hygiene • Confidence correct process has been carried out of individual connectors and provide network operators with the confidence that proper procedures have been correctly carried out. 35 OPTICAL FIBER CONNECTOR HANDBOOK

Inspection Tools for MPO Connectors

The race to deploy Connector inspection for MPO is much more complicated. With current standard Fiber Inspection Probe (FIP) for MPO connectors, the inspection of a single ferrule with multiple connectors requires the operator to focus on one single fiber at a time. The FIP fiber tip comes with a dial which moves the focus from fiber to fiber.

The inspection is tedious and time consuming. In addition, multi- fiber inspection probes the boundaries between Zone C and Zone D is usually not visible to enable proper connector evaluation. Due to the limited magnification, automated qualification for the MPO connector inspection is not available.

The SENKO MPO FIP can inspect all fiber endface at once. The entire connector endface needs to be cleaned even if only one fibre is contaminated.

MPO Tip Up to 24F Available

· For SM & MM MPO (up to 24F) · High precision alignment · Available in APC and PC version

Visualization of MT 12 fiber connector end face (two fibers of MT 12 fiber connector) 36 OPTICAL FIBER CONNECTOR HANDBOOK

Cleaning Tools

Optical cleaning tools are specialized tools which are used to remove connector end face which attracts dust particles. The dry method contaminants from optical connectors and bulk heads. There are two usually cleans the majority of connectors, however, in more severe types of cleaning methods namely the dry cleaning and wet cleaning. cases of contamination, the wet method is more effective. The standard document, ‘IEC 62627-01: Fibre optic interconnecting The main advantage of the wet cleaning method is the active solvent devices and passive components - Technical Report - Part 01: Fibre used in the cleaner which acts as a solvent for oils, raises particles optic connector cleaning methods’ describes a comprehensive to prevent connector end face damage, removes moisture and is cleaning methodology and is usually adopted as the industry’s best fast drying. The most common solvent used in the market is 99.9% practice. isopropyl alcohol (IPA). The presence of a solvent prevents the buildup Dry cleaning is the most common and fastest cleaning method of electrostatic charge on the connector end face. However, the which is used in connector manufacturing plants and in the field. excessive use of solvents may cause the contaminants to be pushed The drawback of the dry method is the risk of potentially scratching to a side of the ferrule and slowly creep back into center after the the end face if there are any hard particles on the connector surface. connector has been inspected and terminated. To prevent such an In addition, some dry cleaners cause electro static charges on the occurrence, a final dry cleaning is performed after a wet clean. The following table outlines the most common dry cleaning tools and the area of use:

Lint free swabs can be used to clean the internal barrel of a bulkhead adapter or the connector end face which is terminated in a bulkhead adapter. Lint Free Swabs If sufficiently large, contaminant on the side of the internal barrel may cause misalignment of two connectors thus increasing the connector insertion loss.

Lint free wipes are not usually used to clean connector end face. The operation of wiping the connector end face with a lint free wipe Lint Free Wipes requires delicate skill to avoid damaging the connector end face.

A small window is opened to expose the cleaning cloth when the lever is pressed. This will also turn the cleaning cloth so that a clean cloth section is used for every clean. The connector end face is pressed and Cartridge Cleaners wiped against the cloth. For a more effective clean, specially treated cleaning cloth that prevents electrostatic charge buildup can be used.

Pen cleaners have a reel of cleaning cloth that rotates at the tip of the cleaner when it is pressed against a connector in a bulk head adapter or directly onto a connector if a fitting is placed onto the tip. This instrument with a “push and click” mechanism cleans the ferrule end Pen Cleaner faces removing dust, oil and other debris without nicking or scratching the end face. There are mainly three types of pen cleaners suitable for 2.5mm, 1.25mm and MPO connectors.

Adhesive backed cleaners have a sticky tip with a soft backing at the top of the cleaner. This cleaner is pressed onto the end face of a Adhesive Backed bare connector or when terminated in a bulkhead adapter. The soft Cleaner adhesive removed dust and other particles.

Compressed air or air duster is used to blow air through the nozzle to get rid of dust on the connector end face. To maintain purity and pressure in the canned air, special material such as difluoroethane or Compressed Air trifluoroethane is used. It is advisable to select a material which has a lower Global Warming Potential (GWP) index. 37 OPTICAL FIBER CONNECTOR HANDBOOK

Wet cleaning is usually done by applying 99.9% isopropyl There is currently no industry standard on the number of iterations alcohol to any of the dry cleaner type in situations when one should attempt to clean the connector end face before disposing contamination on connectors is unable to be cleared from dry cleaning it but the common practice is generally 3 times. Nevertheless, an alone. This usually occurs when contaminant on a connector end face internal guideline should be set in order to avoid wasting time and is left uncleaned for a long period of time. Multiple wet cleaning may resources trying to clean a contaminated/damaged connector. The be required to fully clean a connector end face and must always be diagram below summarizes the recommended cleaning procedure. followed by a final dry clean to remove isopropyl alcohol residue.

Inspect endface is endface Yes Plug into clean with fibre scope clean? mating connector No

Inspect endface Dry Clean with fibre scope

START

No is endface Yes Plug into clean Dry Clean clean? mating connector

Inspect endface is endface Yes Plug into clean with fibre scope clean? mating connector No

Wet clean No immediately followed by Dry clean

Inspect endface is endface Yes Plug into clean with fibre scope clean? mating connector 38 OPTICAL FIBER CONNECTOR HANDBOOK

Cleaning Challenges for MPO Connectors

Unlike single fiber connectors, the cleanliness of the total surface of as the pen cleaner clears contaminants around the optical fiber array. a multi-fiber connector such as the MPO connector is also critical to However the space around the alignment pins remains contaminated. making a proper connection. The array of fibers is presented on a flat A new type of MPO cleaning tool such as the SENKO Smart Cleaner surface which comes into contact when terminated. Any contaminant Stick is able to effectively remove oil, dust and dirt particulate from around the optical fibers and alignment pin prevents full contact pin to pin on the connector endface. An MPO connector is pushed of the two connectors. This creates an air space which reduces the onto the cleaner which sticks onto any contaminant, thus removing connector loss performance. Conventional MPO cleaning tools such any particulate when the connector is removed.

Step 1: Step 2: Step 3: 1 Sticker cleaner contains 10 “Stick” 2 PUSH MT Ferrule against the stick 3 Remove the MT Ferrule, dirt and oil cleaning area surface for cleaner will be transferred from the ferrule to the cleaner

Conventional cleaner NEW “Stick” Cleaner Cleaning Zone cleaning area will clean the full end face

Particles around the pin area can remain which Full surface will be cleaned could cause “air gap.” 39 OPTICAL FIBER CONNECTOR HANDBOOK

IEC Connector type

There are many types of connectors specified under the IEC 61754 family of standards. Such standardization enables a more widespread use of the connectors through a more diverse manufacturers, connector interoperability and connector quality assurance. The list of connectors that are currently specified under the IEC standard is as follows:

1 IEC 61754-2 BOFC Connector 2 IEC 61754-3 LSA Connector 3 IEC 61754-4 SC Connector 4 IEC 61754-5 MT Connector 5 IEC 61754-6 MU Connector 6 IEC 61754-7 MPO Connector 7 IEC 61754-8 CF08 Connector 8 IEC 61754-9 DS Connector 9 IEC 61754-10 Mini MPO Connector 10 IEC 61754-12 FS Connector 11 IEC 61754-13 FC-PC Connector 12 IEC 61754-15 LSH Connector 13 IEC 61754-16 PN Connector 14 IEC 61754-18 MT-RJ Connector 15 IEC 61754-19 SG Connector 16 IEC 61754-20 LC Connector 17 IEC 61754-21 SMI Connector 18 IEC 61754-22 F-SMA Connector 19 IEC 61754-23 LX.5 Connector 20 IEC 61754-24 SC-RJ Connector 21 IEC 61754-25 RAO Connector 22 IEC 61754-26 SF Connector 23 IEC 61754-27 M12 Connector 24 IEC 61754-28 LF3 Connector 25 IEC 61754-29 BLINK Connector 26 IEC 61754-30 CLIK! Connector 27 IEC 61754-31 N-FO Connector 28 IEC 61754-32 DiaLink Connector 29 IEC 61754-34 URM Connector 40 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-2 39.1 BOFC Connector

The Bayonet Optical Fiber Connector (BOFC) is also more commonly Advantages Disadvantages known as the Straight Tip (ST) Connector. The ST Connector was developed by AT&T as a connector which deploys a plug and socket Locking mechanism can be Easy mating and demating misaligned and result in a design. This was the first defector standard for fiber optic cabling and due to spring loaded design misaligned ferrule termination was widely deployed for networking applications in the late 80s and which results in high loss early 90s. The connector has a cylindrical shape connector with a 2.5mm keyed ferrule. The connector and matching adapter has a latch which requires a half-twist bayonet to lock and unlock the connector termination. The ST connector is spring loaded to enable an effortless mating and demating operation. The main application for the ST connector are in CATV networks, LAN and measurement equipment. The popularity of the ST connector is soon overtaken by the FC connector which uses the same twist lock mechanism but with a more compact design. ST Connector

IEC 61754-3 39.2 LSA Connector

The DIN connector was originally standardized by the Deutsches Advantages Disadvantages Institut für Normung (DIN), a German national standards organization. The term “DIN connector” usually refers to a family of round connectors Proven reliability Expensive ferrule design that is usually used for electrical connectivity such as computing data, Compact connector design video and audio. Due to the wide range, the document number of the DIN connector standard is also mentioned to discern specific types of connectors. The optical fiber connector based on the DIN standard is DIN 47256 or also known as the LSA connector. The connector body is similar to the more known FC connector with a screw on connector body. However, the ferrule is much larger. This causes the connector to be much more expensive.

DIN Connectors 41 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-4 39.3 SC Connector

The Subscriber Connector or more commonly known as the SC Advantages Disadvantages connector is designed by NTT, a Japanese telecommunications company, as an improvement over the FC connector. The SC connector Highly popular connector worldwide Large connector footprint compared and for most application to LC connectors is a push/pull type connector which enables a more compact patch panel where traditional FC connectors require additional operation Simple Push/Pull connector operation space to screw and unscrew the connector locking mechanism. In addition, the SC connector push/pull mechanism reduces the time to Compatible with both single mode and terminate connectors. multimode fiber The SC connector has a fully plastic body which is cheaper to manufacture with a moulding compared to machining metallic Available for field installable connector for various fiber and cable sizes connectors. The ferrule size of the SC remains the same as the FC connector with a 2.5mm ferrule.

With increasing deployment of SC connectors in the fiber access network such as FTTH saw the introduction of field installable SC 900um Standard Connector connectors. There are multiple types of SC connectors where the most common types are designed to be compatible with 250µm fiber, 900µm fiber, fiber cords as well as direct termination to the ends of cables such as the hardened SENKO IP Connector. With increasing deployment in network exchange and data centers, field splice-on connectors are introduced. This is an improvement 2.0mm Long Boot on the connector return loss compared to standard field installable connectors which employs a mechanical splice within the connector body. 3.0mm Long Boot

Developments in customer premises fiber termination saw the improvement of network reliability and safety. The auto-shuttered SC connector and adapter were introduced to prevent accidental eye injury from looking directly into an optical connector by users who have no understanding of optical networks and its safety aspect.

SC SHUTTERED Connector IP-SC Connector 42 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-5 39.4 MT Connector

The Mechanical Transfer (MT) Connector was first introduced by NTT in Advantages Disadvantages 1988 as the first multi-fiber termination connector that can terminate Fiber connection is done on a ferrule up to eight fiber cores in one single connection. The connector First introduction of a high fiber termination which has less protection design enables an 8-fiber ribbon can be terminated into a single MT count connector compared to connectors with an body connector which has a 7mm width and 3mm height footprint. Further development of the MT connector saw the introduction of higher Small form factor for high fiber Requires a special tool to demate density designs which enables up to 48 fiber core terminations in a count termination single connector. The MT connector has a male and female design. The male connector Field assembly MT connectors were also introduced for the termination has two guide pins while the female connector has two holes where of up to 12-fiber ribbon. However, the operation to assemble the MT the guide pins are slotted into to align the connector. When the connectors requires high precision alignment to obtain a low loss male and female connectors are terminated, a spring loaded clip is connector for all 12 fiber cores. In addition, the assembly requires the then used to hold the connectors together. To avoid damaging the use of a magnifier as well as a two-part epoxy to hold the fiber in place. connector guide pins, a special MT connector tool is required to remove the spring loaded clip to demate the connector.

Source: Kyoei High Opt 43 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-6 39.5 MU Connector

The Miniature Unit or better known as the MU connector is designed Advantages Disadvantages by Nippon Telegraph and Telephone (NTT) cooperation and is very popular in Japan. The use of MU connectors outside of Japan is very Small Form Factor which is effectively Not widely application outside of half the size of an SC connector Japan limited. Similar to the LC connector, the MU connector is a Small Form Factor (SFF) connector with a 1.25mm ferrule. The MU connector Push/pull locking mechanism makes it looks like an SC connector but at half the size. The connector uses a easy to operate push/pull locking mechanism similar to the SC connector and the MU connector is sometimes referred to as a mini-SC.

The connector features a pre-assembled body and precision molded plastic housing, and a free-floating ferrule held in place with a precision spring. MU connectors are widely used in active device termination, premise installations and telecommunication networks such as FTTH, LAN and WAN. MU with 2.0mm For a patch panel or similar type application, the MU-J type connector Cable Boot is also available. The MU-J is essentially an MU connector without the housing. Together with a short boot, the MU-J type connector is ideal for back panel and high density situations. The MU-J connector is fully compatible with the MU connector when used with a suitable bulkhead adapter.

MU with 1.0mm Fiber Boot

MU with 1.0mm Fiber Short Boot 44 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-7 39.6 MPO Connector

The MPO connector was first introduced by NTT in the 1990’s as a The MPO is separated into a male and female connector. The male solution to a growing FTTH fiber access network. The connector is connector has two guide pins that slots into two holes of the female based on the MT ferrule technology introduced in 1985 by NTT that connector within the MPO adapter to align the ferrules for connector was also used in the MT-RJ connector. The MT-RJ has only two fibers termination. As a general practice, the male connector is usually with a 750μm pitch within the ferrule, however MPO connectors can terminated in the patching back panel, wall outlets or transceivers have an MT ferrule with a fiber count ranging from 4 to 72 fibers. The while the female connector is used at the ends of jumper cords. This MT ferrule is typically manufactured by using Polyphenylene Sulfide, practice is to set the male connectors in a static position to protect the which is a glass filled engineering polymer which has a thermal guide pins from accidental damage. stability very close to glass. While there are many MT ferrule based connectors, the MPO is the most common.

The MPO connector has a similar footprint as an SC connector at 82mm2, however the MPO has a rectangular shape instead of square. Comparing an SC connector with a 72-fiber MPO connector, the fiber density of the MPO connector is 1.3mm2 per fiber. This is 63 times the density of an SC connector.

MPO Male Connector

Key Up Key Down

MPO Female Connector

Key Up Key Down 45 OPTICAL FIBER CONNECTOR HANDBOOK

Due to the multi-fiber array of The MPO connector, it is Before deploying MPO connectors, the end-to-end network design important to ensure that every fiber in the connector must be decided. This includes the polarity of the MPO connector. As can achieve a high attenuation and return loss performance. The with any patch panel involving MPO connectors, a fan-out from an connector performance depends on multiple factors such as the MPO to individual connectors, such as an LC connector is required. fiber-hole position, fiber-hole diameter tolerances, fiber protrusion In duplex networks such as a DWDM transport network, a pair of level, connector endface angle, alignment pin and hole tolerances fibers is required for the uplink and downlink. The confirmation of and connector cleanliness. these three parts of the network will help determine the two types of MPO polarity for the MPO-MPO jumper and the MPO adapter key orientation. The polarity types are as shown below:

Straight thorugh Fiber MPO Jumper

Position 1 Fiber 1 Position 1

Position 12 Fiber 12 Position 12

Flipped Fiber MPO Jumper

Position 1 Fiber 1 Fiber 12 Position 1

Position 12 Fiber 12 Fiber 1 Position 12

Key Down/Key Up Adapter

Position 1 Position 1

Position 12 Position 12

Key Up/Key Up Adapter

Position 12 Position 1

Position 1 Position 12 46 OPTICAL FIBER CONNECTOR HANDBOOK

More features, same cost

More features, compared to conventional MPO

Bare Ribbon Fiber Mini Bare Ribbon Fiber Short

Ribbon Cable Flex Angle Boot 47 OPTICAL FIBER CONNECTOR HANDBOOK

SENKO has a range of MPO connector solution for different deployment situation. A few of the solutions are: Mini Connector ength Short L • MPO Mini of 37mm for 3mm round Features a shorter boot for space constrained situations and enables polarity change in the field without any special tool and changing the connector gender in the field.

• MPO Micro Enables an MPO connection without the connector housing. Able to mate/de-mate the connector with a simple tool.

• MPO Bayonet Micro Connector Unique micro housing/ Integrated turn lock connector boot to prevent accidental ferrule design Push-in and connector de-mating. Removal tool

• MPO Latch MPO connection with no housing that locks into a latch ready MPO Micro Connector ready Adapter adapter. The latch ready adapter is also compatible with conventional MPO connectors.

• MPO-HD MPO connector with a pull-tab release trigger which allows the connector to be easily disengaged without the need of a special Bayonet Connector tool. This allows the connector to be densely packed.

• IP MPO MPO connector within an external housing for harsh environment application.

Advantages Disadvantages Multiple fiber termination in a single Requires all fibers to be properly connector terminated for a high quality connector Most compact fiber connector All fiber terminations are affected if available in the market today with up the connector needs to be de-mated to Bayonet Connector to 72 fiber terminations in a single perform any operation on a single fiber connector in the connector Easy Simple push/pull operation The simple push/pull connector design assembly without a latch is simplistic for a high fiber count termination easy handling Lowest cost per fiber termination Operator needs to be clear on the among all fiber connector types connector polarity Growing in popularity for telecoms exchange and data center networks 48 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-8 39.7 CF08 Connector

The parent connector for the type CF08 connector family is a single- the optical axis. The plug has a single male key which may be used to way plug connector which is characterized by a conical ferrule butting orient and limit the relative rotation between the connector and the against a 4 mm diameter sphere or equivalent. It includes a push-pull component to which it is mated. coupling mechanism and a ferrule spring loaded in the direction of

IEC 61754-9 39.8 DS Connector

The DS connector is also known as the F11 type connector based on the Japanese standard JIS C 5980. The connector was only deployed in very niche applications. The DS connector has a 2.5mm ferrule and has an integrated sleeve design.

Source: Tonichi Kyosan Cables IEC 61754-10 39.9 Mini MPO Connector

The Mini-MPO connector was developed based on the standard MPO Mini MPO MPO connector. The mechanism for the mating/demating and ferrule polishing is exactly the same as the standard MPO connector. The 6,4mm 4,4mm objective of the Mini-MPO connector is to increase the connection density of up to four optical fibers. Although the standard MPO 2,5mm 2,5mm connector can be manufactured for four fibers, the large MT ferrule FERRULE 4,6mm 2,6mm size requires high accuracy in fiber endface geometry to achieve perfect physical contact. The Mini-MPO uses a ferrule smaller than the MT, with the pitch 9,6mm 7,2mm between the connector guide pins to be reduced from 4.6mm of the MPO connector to 2.6mm. The structure of the Mini-MPO adapter 4,0mm

is also simplified by using a guide sleeve that is inserted into the 5,0mm

coupling sleeve instead of a reinforcing member. A table comparing CONNECTOR the MPO and Mini-MPO connector is as shown below.

6,4mm 10mm Advantages Disadvantages Smaller connector footprint Only up to 4 fibers per connector APTER 8,0mm D 9,8mm

Higher insertion loss and return Less fiber per connector area density A loss performance compared to MPO compared to standard MPO connector connector 49 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-12 39.10 FS Connector

The FS connector is a duplex connector where the connector has Advantages Disadvantages a pair of cylindrical spring loaded abutting ferrules of 2,5 mm Has multiple keyway arrangements to Large connector footprint nominal ferrule diameter. The optical alignment mechanism is a rigid enable specific connector and adapter bore or resilient sleeve contained within the adaptor. It includes a mating hand-released latch coupling. The connector has multiple keyway arrangements and the adaptor has multiple key configurations. The keying scheme is exclusionary and is used to limit mating between connector and adaptor to specific key combinations

IEC 61754-13 39.11 FC Connector Advantages Disadvantages One of the first fiber optic connector Machined metallic body is expensive to with a zirconia ceramic ferrule manufacture Requires screwing and unscrewing Locking mechanism suitable for use in which increases installation time and high vibration environment more operation space around the bulkhead adapter FC Square Adapter, Solid Body Different connector standards may Connector design reduces tension on confuse user or result in sub-optimal optical fiber performance FC Oval Adapter, HD Style FC Round Adapter, D Style

The Fiber Connector or more commonly known as FC connector is onto the bulkhead adapter for connector termination. This connector designed by NTT as an improvement of the ST connector which was was widely used in all optical network when it was first introduced due the first introduction of an optical connector with a 2.5mm ceramic to its high connector reliability and performance. The FC connector is zirconia ferrule. This connector with a locking mechanism is designed no longer widely deployed after the Introduction of the SC connector. to be used in high vibration environments. The connector is commonly However, the FC connector is still commonly used in optical testing used in telecommunication networks, data centers and measurement equipment such as the Optical Time Domain Reflectometer (OTDR) equipment with singlemode fiber as well as polarization-maintaining and Optical Continuous Wave Reflectometer (OCWR). optical fiber. There are four standards for the FC connector. One standard for Metallic ferrules have a different expansion coefficient compared the FC/PC connector, two standards for the FC/APC connector and to optical fibers. This caused the epoxy adhesive to fail when the another standard which is applicable to either type of polishing. These metallic ferrule expands and contracts with the change in ambient standards differ in the width of the alignment keys. temperature. This is a process called “pistoning”. Ceramic ferrules have For the FC/APC connector types, one of them is referred to the “NTT” a coefficient of expansion that is closer to optical fiber thus eliminating or “type N” connector which has a key width of 2.09–2.14mm and an the adhesive failure. adapter key width of 2.15–2.20mm. The other standard is known as the The FC connector has a screw on connector body which locks the “type R” which refers to its reduced key width. The type R connector connector body, isolating the cable tension from the ferrule. The FC key width is 1.97–2.02mm and the adapter key width is 2.03–2.08mm. connector and bulkhead adapter has an alignment key to enable The type R connector can be mated with a type N adapter, however correct ferrule orientation especially for angle polished ferrules. The the connectors in the adapter may not be precisely aligned, thus bulkhead adapter of the FC connector has a metallic barrel which reducing the connector attenuation and return loss performance. The becomes a risk for damaging the ferrule when it is improperly inserted. type N connector cannot be terminated into a type R adapter as the The FC connector has a machined metallic body which is screwed connector key is wider than the adapter key slot. 50 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-15 39.12 LSH Connector

The LSH connector, more popularly known as the E2000 connector, Advantages Disadvantages is produced under license of Diamond, a Swiss company specialized Connector with integrated auto-shutter High cost for a connector performance in customizing components and equipment. The E2000 name is and adapter can also be shuttered similar to an SC connector also trademarked by Diamond. The E2000 connector is also mainly manufactured by Reichle & De-Massari (R&M) and Huber Suhner Have the option to include an O-ring seal for an IP65 rated connector under the license of Diamond. The E2000 connector is a plastic push/pull connector with a 2.5mm ferrule. The E2000 has a latch similar to an LC connector which holds the connector in the bulkhead adapter to prevent accidental pull out. E-2000 APC In addition, the E2000 has an improvement by having a built-in dust cap which automatically shuts when the connector is not terminated. The auto shutter is designed with a lever at the top that is pushed to open the shutter when it is inserted into the bulkhead connector. This allows the connector ferrule endface to always be covered until it is terminated to prevent contamination as well as provide protection Connector Lever against accidental laser exposure. The connector is used mainly in high safety and high powered transmission such as in DWDM networks. In such high powered E-2000 UPC networks, the E2000 adapter has an angled, anti-reflection surface that induces light diffusion and low reflectance when unmated. The adapter can also have an auto shutter which blocks laser light from escaping an unterminated adapter. Crimpset In a harsher environment such as in an underground closure patch panel, there is a possibility of water ingress in the closure when

it is improperly sealed. In such cases, optical connectors in the E 2000 Multimode compromised closure will experience reduced performance due to contamination. The E2000 connectors and adapters can have an additional O-ring seal which makes the connector itself have an IP65 rating. This prevents water from entering the adapter barrel where the ferrules mate.

IEC 61754-16 Advantages Disadvantages 39.13 PN Connector Uses both lever locking and friction locking High loss connector mechanism for high connection reliability The PN Connector is also widely known as Plastic Fiber (PF) connector. This connector is used mostly for Plastic Optical Fiber (POF) multimode application. The connector has a duplex design with both the lever locking and friction locking mechanism.

Source: Honda Tsushin Kogyo 51 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-18 39.14 MT-RJ Connector

Advantages Disadvantages MT-RJ Female Connector Standard Inherently a duplex connector that is Very poor single mode performance and suitable for a multimode network. higher connector cost Small form factor connector reduces Male/female connector incompatibility patch panel real estate requirement Difficult to test as most test equipment do not have a direct connector termination to the MT-RJ connector. MT-RJ Male Connector Standard Requires an intermediate patch cord to convert to an SC or FC type connector. The Mechanical Transfer Registered Jack, or better known as the MT- 750µm fiber pitch is a mismatch with RJ, connector was introduced by AMP in the late 90’s as a low cost standard fiber buffer coating. connector that looked like the copper RJ45 style connector. The Complicated process for proper connector is a Small Form Factor (SFF) duplex connector, with two termination in a FIC assembly. fibers in a single connector, designed to terminate into an Ethernet port of a computer modem or router. A single mini MT plastic ferrule differs. This causes a varying connector coupling performance houses two fibers spaced 750µm apart instead of the more prevalent from different manufacturers which complicates the connector ceramic zirconia ferrule. The connector is based on the multi-fiber MT performance consistency. ferrule designed by NTT. Due to the unique ferrule, the initial cable designed to be terminated The MT-RJ connector is usually used for multimode optical fiber but with the MT-RJ connector was a two fiber ribbon which separates the is also applicable in single mode networks. The connector is a Small fiber with a 750µm pitch which is similar with the fiber pitch in the Form Factor (SFF) duplex connector. The MT-RJ connector is used ferrule. Although cord construction eases the fiber insertion process more in multimode networks due to the lower cost to manufacture into the MT ferrule, it complicates the process when a hybrid patch the glass-filled thermoplastic ferrule by standard injection molding cord is manufactured. The second cord design iteration include a compared to a single mode ferrule that requires a more precise two 250µm fiber within a 900µm buffer tube which was suitable for glass-filled thermoset ferrule that must be transfer molded, which is a hybrid jumper manufacturing but complicated the fiber insertion a slower process. process into the MT ferrule. The third iteration was two 900µm buffer The MT-RJ is separated into a male and female connector. The male tube within a jumper but this design still presents a complication in connector has two guide pins that slots into two holes of the female the fiber insertion process. To overcome the fiber pitch issue, some connector within the MT-RJ adapter to align the ferrules for connector connectors are designed with a fiber transition boot that guides the termination. As a general practice, the male connector is usually fiber into a 750µm pitch. terminated in the patching back panel, wall outlets or transceivers A field installable MT-RJ connector but the assembly was complicated while the female connector is used at the ends of jumper cords. This and requires specialized tools such as a crimping tool, VFL with dual practice is to set the male connectors in a static position to protect light source and an MT-RJ to two simplex connectors are required the guide pins from accidental damage. A male to female patch cord to terminate the fibers. The fiber preparation requires both fibers is used in the event where a mid-span connection is required. Some to be stripped and cleaved with the same length. During the fiber unique MT-RJ connectors allow for the guide pins to be removed or insertion process, both fibers need to be inserted at the same time inserted to interchange the connector gender. and the insertion length must be similar to prevent one fiber from The connector has a latch that is designed similar to the copper over bending within the connector boot. In addition, the operator RJ45 connector. A single latch positioned at the top of the connector must be very clear on the polarity of the fibers. Due to the high skill locks the connectors within the bulkhead adapter. Depending on the required and the high potential for failure, the field installable MT-RJ connector material, latch angle and arm deflection, the latch strength was not popular. 52 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-19 39.15 SG ConnectorMT-RJ Connector

The SG connector, or better known as the Volition VF-45 connector, Advantages Disadvantages was developed by 3M as a low cost solution for fiber interconnectivity Low cost without the use of ferrules Proprietary connector design by 3M for fiber-to-the-desktop application. The connector removes the need for ferrules but instead uses the v-groove fiber alignment technology. Uses the familiar RJ-45 style latching Only sockets can be field assembled The connector is designed to have the same appearance and Easy field assembly for sockets operation of a standard RJ45 connector. Suitable for Single Mode and Multi Mode fiber The VF-45 connector is factory terminated with a fiber holder which secures two or more fibers in place, a shroud and boot which protect the fibers and secure the cable to the connector and an integral door which acts as a dust cover. The VF-45 socket is field assembled without the need of precision alignment tools. The v-groove aligns the fibers within the socket and a mechanical grip holds the fibers securely in place. The field assembled sockets are installed into wall outlets and patch panels similar to RJ45 keystones.

Source: 3M 53 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-20 39.16 LC Connector

The LC connector is designed by Lucent Technologies as the next generation Small Form Factor (SFF) connector with a 1.25mm ferrule. This is effectively half the size of an SC connector. The connector uses a retaining tab mechanism to lock the connector when plugged into a bulkhead adapter for a single fiber termination. LC connectors also come in a duplex form for two simplex fiber terminations or quad form for four simplex terminations. 900µm MINI Boot LC connectors have been gaining popularity due to its small footprint which saves precious network space and is currently the most common SFF connector. The LC connector can be used with singlemode and multimode fiber. The main area of application are telco networks such as FTTH, LAN, data processing, device termination, CATV, cell towers & antennas. Further development of the LC connector latching mechanism and 2.0mm MINI Boot boot enables the connector to be further packed into a smaller space. The SENKO LC-HD connector has a pull tab which activates the latching mechanism which releases the connector from the bulkhead adapter. This removes the need for “finger space” between connectors to fit an operator’s fingers to push onto the latch. With an increased connector density, connector identification 3.0mm MINI Boot becomes complicated. Such problems can be solved with new connector identification technology such as RFID tagging and visual LED lighting system. One such example is the SENKO EZ-Trace LC which indicates the connector at the far end when a button on the connector is pushed.

Push the button to The LED starts Flashing The LED light is Visible on the 1 activate the LED 2 emitting a red light 3 other end of the patch cord

LED Traceable Light how to: 54 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-21 39.17 SMI Connector

Molex developed the Small Multimedia Interface (SMI) for Plastic Advantages Disadvantages Optical Fiber (POF) connector and transceiver system. The SMI Low cost connector solution Limited bandwidth and distance connector was designed to be a low-cost solution for home and industrial transmission system. The connector is mostly used in home Easy field termination solution networking, High Definition video display, home audio and theater system as well as industrial network. The connector has a no-epoxy, no polish solution enables a quick The SMI is a duplex connector system that can operate at S200 and simple field-termination process. The SMI solution also includes (250Mbps) speeds for up to 50 meters and S400 (500Mbps) in the a transceiver with a digital integrated fiber optic transmit and receive future. The SMI has a push-pull positive latching with a safe-release modules. mechanism.

Source: Design World IEC 61754-22 39.18 F-SMA Connector

The F-SMA connector is one of the first generations of fiber optic Advantages Disadvantages connectors. The connector uses a metallic ferrule where the fiber end Connector suitable for high powered High cost is free from epoxy glue. This allows for better thermal dissipation in the application connector fiber region of maximum power density. The body of the connector and adapter are metallic and is a screwed on design.

The connector is designed for multimode fiber use and is mainly used in high powered application such as industrial and medical systems where short and medium range performance is required.

Source: Diamond 55 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-23 39.19 LX.5 Connector

The LX.5 connector was introduced by AMP in the late 90’s as one Advantages Disadvantages of the many Small Form Factor (SFF) connectors that gained in Small Form Factor connector that can Less robust than the standard LC popularity. The LX.5 was marketed as part of ADC’s premises cabling be duplex connector system called Enterprise. The LX.5 connector adoption is largely confined within the European markets. Shuttered connector Not widely adopted in the market Similar to most SFF connectors at that time, the LX.5 connector uses Latching mechanism to prevent a 1.25mm ferrule in a connector. The connector and the shutter has unintentional disconnection a built-in shutter designed for eye safety. The spring loaded shutter automatically rises as the connector fits into the adapter and returns to fit over the ferrule when the connector is removed. The LX.5 is available in a simplex and duplex form as single mode and multimode. The LX.5 connector also has an integrated latching mechanism that locks the connector into the adapter to prevent unintentional disconnection.

Source: Huber + Suhner IEC 61754-24 39.20 SC-RJ Connector

The Subscriber Connector Registered Jack (SC-RJ) is a push/pull Advantages Disadvantages Small Form Factor (SFF) developed by Reichle & De-Massari (R&M) Able to be used for all types of fibers Not widely adopted primarily for Ethernet and Fast Ethernet network connections of up to 100Mbps. The SC-RJ is the first connector to be specified for used with Available in IP67 option Difficult to prepare the field installable all fiber types which are glass optical fiber, polymer optical fiber and connector plastic cladded fiber. The connector can be used for both multimode and single mode fiber.

On first look, the SC-RJ looks very similar to an SC duplex connector but there is a difference. Although the SC-RJ is based on the better known SC connector technology, the size of the SC-RJ is suitable to be fitted within a standard RJ45 connector. Similar with the SC connector, the SC-RJ connector uses the 2.5mm ferrule. The SC duplex connector has two keys on top of each connector. However the SC-RJ connector has three keys, one each facing the left, top and right side of the connector. The connector is specified for use with The SC-RJ is mainly used in office networks, campuses and industrial application. R&M has also developed an IP67 SC-RJ connector for higher environmental protection especially in industrial conditions. In addition, a field installable solution is also available, however the fiber preparation is very tedious, requiring the cord and fiber length to be accurate as well Source: RDM as the fiber polarity. 56 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-25 39.21 RAO Connector

The RAO connector is a multi-fiber connector which uses the MT Advantages Disadvantages ferrule. This connector is designed with a built-in right-angled bend. Multi-fiber termination Requires four MT ferrules Due to the right-angled bend design, the connector requires the use in a single connector even if less fiber termination is needed of fiber with low bending loss at 30mm bending radius so that the radius of curvature at the 90 degree bend is maintained with a low permissible loss. The optical connection is the physical contact of optical fibres with the rectangular MT ferrules with nominal dimensions of 6.4mm x 2.5mm which uses two 0.7mm diameter alignment pins. The RAO connector enables the termination of up to four MT ferrules in a single termination. Even when less connections is required, the connector needs to termination of four MT ferrules to maintain the connector balance. This connector is mainly used in equipment termination board and for fiber testing equipment.

IEC 61754-26 Source: IEC 39.22 SF Connector

The SF connector is a low cost, high density connector developed by Advantages Disadvantages NTT. The connector is designed to enable a direct multi fiber contact High density Weak connector that is only suitable to by using micro holes without the need for ferrules. This allows the and low cost connector be used in a protected environment SF connector to have a manufacturing cost of nearly a quarter of standard multi-fiber connectors such as the MPO connector. Multi-fiber termination in a single connector

The connector is a plug which holds multiple fibers that are laid out in a plane. The ends of the cleaved fibers protrude out of the plug. The connector is terminated into a receptacle block that has micro holes to align the fibers. One side of the fibers in the plug has a very small micro bend when fully terminated. This is to ensure that the end faces of the terminated fiber is pushing onto the fibers on the other side. When two SF connectors are terminated into a receptacle block, a clip similar to the MT connector is used to hold the connectors together. The SF connector is mostly used for fiber termination in equipment which has space constraints.

Source: NTT 57 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-27 39.23 M12 Connector

The M12 connector is a robust and watertight connector that is Advantages Disadvantages suitable for glass optical fiber, plastic optical fiber and photonic- Highly robust connector High cost connector crystal fiber. The connector is designed to protect the dual 2.5mm for industrial application due to robust design. ferrules endfaces during termination. Depending on the connector design, the M12 connector can have an IP65 or IP67 protection. The dual ferrules are at a level below the connector housing, thus they are not exposed. The connector and adapter has notches which aligns the connector before the ferrules are slid into the adapter barrel. This ensures that the ferrules are not accidentally damaged during connector termination. The M12 connector is usually used in industrial application where a more rugged connector assembly is required with a high IP rating, tear-resistance, strain relief and other environmental protection such as UV resistance.

Source: Phoenix Contact

IEC 61754-28 39.24 LF3 Connector

The LF3 or better known as the F-3000 connector was developed Advantages Disadvantages by Diamond as the next evolution from their E-2000 connector. The Small Form Factor connector F-3000 connector was standardized as the LF3 connector in the IEC- High cost connector that can be duplex 61754-28 standard.The F-3000 connector includes all the technical, mechanical and optical features of the E-2000 connector in a Small Shuttered connector and adapter Not widely adopted in the market Form Factor (SFF) footprint. The connector is available as a simplex, Latching mechanism to prevent duplex as well as for backplane application. The connector is fully unintentional disconnection compatible with the more widely deployed LC connector. The F-3000 connector uses Diamond’s patented two-part ferrule and Active Core Alignment (ACA) technology. The assembly involves two crimping tools that determines the position of the ferrule center location and pushes the optical fiber core towards this center location. This ensures the core concentricity error to be less than 0.2μm.

Source: Diamond 58 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-29 39.25 BLINK Connector

The BLINK connector was introduced by Huber+Suhner as a customer Advantages Disadvantages premises connection from the Internal Termination Point (ITP) to the Customer Premises Equipment (CPE) such as the Optical Network Shuttered connector and adapter Proprietary connector and system Terminal (ONT). Taking into consideration of general end customers Higher cost compared to Auto disengage feature who do not have the skill nor experience in handling optical fiber conventional patch cords termination, the BLINK connector is designed to be a simple to use jumper similar to an Ethernet cable. The BLINK connector follows the standard Small Form Factor (SFF) connector size and uses a 1.25mm ceramic zirconia ferrule. The BLINK connector and adapter is designed to have an automatic metallic shutter to protect the endface of the connector and adapter from dust and mechanical damage. In addition, it also acts as a safety feature to prevent exposure to laser light. One additional feature of the BLINK connector is the auto disengage from the adapter when the cable is accidentally pulled. Although the connector can withstand 100N tensile load, this feature prevents Source: Huber + Suhner connector damage from a sudden high tensile stress. This design is connectors that will be installed by trained fiber technicians. similar to standard home cabling for power, HDMI or USB connection. A new keystone adapter, also known as modular jacks, is designed to The BLINK adapter is designed to enable connection to the BLINK enable the fiber termination from a pre-terminated CLIK! Connector connector to standard LC or SC connector. The design enables the at the back and the BLINK connector from the front. This enables fiber outward facing side of the adapter to be terminated with the BLINK termination to be available in existing keystone outlets rather than connector but the inward side to be suited for conventional LC and SC needing a new fiber outlet.

IEC 61754-30 39.26 CLIK! Connector

The CLIK! System was introduced by Huber+Suhner in 2011 for Master Advantages Disadvantages Antenna Television (MATV) and Direct-To-Home (DTH) applications. The system enables a quick and easy method to divide signal from a Small connector enables pre-terminated Proprietary connector and system cable hauling through existing conduit fiber optic Low Noise Block (LNB), designed for commercially available satellite systems, with matching splitters to deliver signal to multiple Connector has an integrated pulling eye customer premise equipment. The CLIK! System aims to replace conventional coaxial cable network for satellite signal distribution. The CLIK! System is currently deployed in Switzerland, Italy, Austria and Germany. The CLIK! System aims to use existing ducting within a customer premise and using existing cabling within the duct as a pull cable to haul in new fiber optic cable. The connector is designed to have a small 5mm diameter suitable for hauling in ducting. In addition, the connector is designed with a pulling eye to enable up to 100N pulling tension. The connector can then be terminated into a splitter unit for distribution throughout the customer premise. The CLIK! System includes a two-way and a four-way splitter, each with different distribution requirements that are used based on cable lengths and connectors. Three-way and five-way splitters will also soon be available.

Source: Huber + Suhner 59 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-31 39.27 N-FO Connector

The N-FO connector which is also known as the ODC (OutDoor Advantages Disadvantages Connector) was introduced by Huber+Suhner in 2015 as a robust Robust connector suitable for harsh Proprietary connector and system connector for Remote Radio Head (RRH) terminations. Huber+Suhner environment identified that damage to optical fiber interfaces is one of the main causes of defects during RRH installations, thus the ODC is designed Multi fiber connector as a robust outdoor connector to handle harsh environments and rough handling. The ODC family comprises of a two-way and four-way push-pull circular plug connector and socket set. Each fiber is housed within a spring loaded 1.25mm ceramic non-angled ferule. The plug connector has a key which fits into the socket keyway to align the connector ferrules before termination. The socket has a spring loaded threaded coupling nut which can be tightened after the connector is terminated. The ODC provides harsh outdoor environment protection where RRH are installed such as in coastal areas, urban buildings or rural tower sites. The ODC can withstand temperature extremes, vibration, salt mist, corrosive gases and high humidity. Source: Huber + Suhner

IEC 61754-32 39.28 DiaLink Connector

The DiaLink connector family was introduced by Diamond in 2016 Advantages Disadvantages as a flexible pre-terminated fiber optic cabling solution suitable for Small footprint enables easy installation in confined spaces with its slim 6mm connector design. Proprietary connector and system installation in confined spaces The DiaLink connector is designed for a wide range of application DiaLink-Saver have integrated including FTTH deployment, fiber optic LAN and medical applications. Only available in a simplex connector connector end face protection DiaLink uses a 1.25mm ferule in a simplex connector with a push-pull design mechanism coupling mechanism. DiaLink has a male and a female connector side. To provide adequate ferule contact, the male side of the connector has a spring-loaded ferule while the female side has a fixed ferule. The connector does not require an adapter for termination. Instead, the fixed-ferule side of the connector has an integrated adapter sleeve to provide connector alignment. The DiaLink-Saver connector is designed with a breakaway coupling device. The connector separates the fiber optic termination when subjected to a sudden pull force where the separated connectors can be easily re-terminated without the need of special tools. The end faces of disconnected DiaLink-Saver connectors are protected from the environment, thus they can be re-terminated without the need for end face cleaning. There are also adapters available to terminate a

DiaLink connector to an E2000 connector. Source: Diamond 60 OPTICAL FIBER CONNECTOR HANDBOOK

IEC 61754-34 39.29 URM Connector

The URM (yoU aRe Modular) fiber optic connector is introduced by Advantages Disadvantages EUROMICRON Werkzeuge GmbH, a company that specialized in Low loss connector alternative to MPO Proprietary connector and system high-tech solutions for digital buildings, smart industry and critical connector for data center application infrastructure. The URM connector was certified in the IEC 61754-34 standard in October 2016. High density and modular design The URM is a modular multi-fiber connector system with a small form factor design for high density data center network application as a higher performance alternative to MPO connectors. The connector is available as a two fiber and eight fiber connector with both PC and APC polished ferule. Unlike MPO connectors where multiple fibers are terminated in a single connector, each fiber in the URM connector is guided within their individual 1.25mm spring loaded ceramic ferule. This enables each fiber end face to be polished separately. The connector termination alignment is guided by a resilient sleeve. The modular design of the connector also enables the connector polarities to be changed. The URM connector is specified to achieve low insertion loss of less than 0.2dB. This is critical in low loss budget links such as 100GbE and 400GbE links. Source: Euromicron 61 OPTICAL FIBER CONNECTOR HANDBOOK

Acknowledgement

The development of this white paper beneﬁted signiﬁcantly from the input and support provided by our partner, JGR Optics Inc. Their feedback and guidance has provided invaluable insights, and the background information they provided has been vital to the development of this white paper. We would like to give special thanks to each member of their team for sharing their time and expertise with us.

Biography

Bernard H. L. Lee is currently the Regional Technology Director at SENKO Advanced Components. He started his career in optical communications in 2000 as a Senior Research Ofﬁcer for DAVID, a European Union IST project. In 2003, he joined the R&D division at Telekom Malaysia, where he held various technical and management positions, including Head of Photonic Network Research and Head of Innovation and Communications, before joining the parent company in 2010 as Assistant General Manager of the Group Business Strategy Division, where he oversees the company’s business direction. Bernard is also a member of the International Electrotechnical Commission (IEC) and the Institute of Engineering and Technology (IET), and has served on the Board of Directors of the Fiber-to-the-Home Council APAC.

Tomoyuki (Tom) Mamiya currently manages Engineering and QA Group of SENKO Japan. He joined SENKO Japan in July 1999, and then joined SENKO Advanced Components in the United States to manage all global engineering efforts as a Engineering Manager in February 2000. He worked in various engineering and product development positions before being promoted to Global Vice President of Engineering in 2006. Prior to joining SENKO, he had worked for fiber optic component and equipment manufacturing company in Japan for more than 5 years as R&D engineer. He hold over 10 patents in fiber optic component field in world-widely, in the US, Euro, Japan, and Taiwan. 62 OPTICAL FIBER CONNECTOR HANDBOOK