Photodetectors for Lidar
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Light Sources and Photodetectors for OBS® Sensors Application Note
APPLICATION NOTE APPLICATION App. Note Code: 2Q-R Written by John Downing Light Sources and Photo- detectors for OBS® Sensors ® CAMPBELL SCIENTIFIC, INC. WHENW H E N MEASUREMENTSM E A S U R E M E N T S MMATTERA T T E R Copyright (C) April 2008 Campbell Scientifi c, Inc. Light Sources and Photodetectors for OBS® Sensors Sensors that use the OBS® method have narrow- or intermediate-band illumination systems, depending on whether a laser diode (LD) or infrared-emitting diode (IRED) is used in their construction. This application note describes infrared-emitting diodes and laser diodes, as well as photodiodes, daylight fi lters, and operating spectra. Laser Diodes Laser diodes have narrow, multimode emission spectra resembling the one shown in Figure 1. The LD bandwidth is about 2 nm at half power (FWHM). They have built-in photodiodes to monitor the light output of the laser chip so that photocur- rent can be used to control the illumination of the sample. In this way, fluctuations in light power caused by sensor temperature and laser aging are virtually elimi- nated. The drift of our OBS-4 LD-based sensor, for example, is less than 2% per year of continuous operation. The two disadvantages of lasers are that they emit coherent light, which because of interferences can fluctuate in intensity in a sample volume by as much as 50%, and they are less efficient in converting electrical current to light than IREDs. Figure 1. Graph shows the relative power, transmission and responsivity of a laser diode. Laser diodes have narrow, multimode emission spectra. -
Photodiode and LIGHT EMITTING DIODE
Photodiode and LIGHT EMITTING DIODE Presentation by JASWANT KUMAR ROLL NO.-12 rd IT(3 SEM.) 1 About LEDs (1/2) • A light emitting diode (LED) is essentially a PN junction opto- semiconductor that emits a monochromatic (single color) light when operated in a forward biased direction. • LEDs convert electrical energy into light energy. LED SYMBOL 2 ABOUT LEDS (2/2) • The most important part of a light emitting diode (LED) is the semi-conductor chip located in the center of the bulb as shown at the right. • The chip has two regions separated by a junction. • The junction acts as a barrier to the flow of electrons between the p and the n regions. 3 LED CIRCUIT • In electronics, the basic LED circuit is an electric power circuit used to power a light-emitting diode or LED. The simplest such circuit consists of a voltage source and two components connect in series: a current-limiting resistor (sometimes called the ballast resistor), and an LED. Optionally, a switch may be introduced to open and close the circuit. The switch may be replaced with another component or circuit to form a continuity tester. 4 HOW DOES A LED WORK? • Each time an electron recombines with a positive charge, electric potential energy is converted into electromagnetic energy. • For each recombination of a negative and a positive charge, a quantum of electromagnetic energy is emitted in the form of a photon of light with a frequency characteristic of the semi- conductor material. 5 Mechanism behind photon emission in LEDs? MechanismMechanism isis “injection“injection Electroluminescence”.Electroluminescence”. -
Integrated High-Speed, High-Sensitivity Photodiodes and Optoelectronic Integrated Circuits
Sensors and Materials, Vol. 13, No. 4 (2001) 189-206 MYUTokyo S &M0442 Integrated High-Speed, High-Sensitivity Photodiodes and Optoelectronic Integrated Circuits Horst Zimmermann Institut fiirElektrische Mess- und Schaltungstechnik, Technische Universitat Wien, Gusshausstrasse, A-1040 Wien, Austria (Received February 28, 2000; accepted February3, 2001) Key words: integrated circuits, integrated optoelectronics, optical receivers, optoelectronic de vices, PIN photodiode, double photodiode, silicon A review of the properties of photodiodes available through the use of standard silicon technologies is presented and some examples of how to improve monolithically integrated photodiodes are shown. The application of these photodiodes in optoelectronic integrated circuits (OEICs) is described. An innovative double photodiode requiring no process modificationsin complementary metal-oxide sem!conductor (CMOS) and bipolar CMOS (BiCMOS) technologies achieves a bandwidth in excess of 360 MHzand data rates exceeding 622 Mb/s. Furthermore, a new PIN photodiode requiring only one additional mask for the integration in a CMOS process is capable of handling a data rate of 1.1 Gb/s. Antireflection coating improves the quantum efficiencyof integrated photodiodes to values of more than 90%. Integrated optical receivers for data communication achieve a high bandwidth and a high sensitivity. Furthermore, an OEIC for application in optical storage systems is introduced. Author's e-mail address: [email protected] 189 l 90 Sensors and Materials, Vol. 13, No. 4 (2001) 1. Introduction Photons with an energy larger than the band gap generate electron-hole pairs in semiconductors. This photogeneration G obeys an exponential law: aP,0 G( x) = -- exp( -ax), Ahv (1) where xis the penetration depth coordinate, P0 is the nonreflectedportion of the incident optical power, A is the light-sensitive area of a photodiode, hv is the energy of the photon, and a is the wavelength-dependent absorption coefficient. -
Semiconductor Light Sources
Laser Systems and Applications Couse 2020-2021 Semiconductor light sources Prof. Cristina Masoller Universitat Politècnica de Catalunya [email protected] www.fisica.edu.uy/~cris SCHEDULE OF THE COURSE Small lasers, biomedical Semiconductor light sources lasers and applications . 1 (11/12/2020) Introduction. 7 (19/1/2021) Small lasers. Light-matter interactions. 8 (22/1/2021) Biomedical lasers. 2 (15/12/2020) LEDs and semiconductor optical amplifiers. Laser models . 3 (18/12/2020) Diode lasers. 9 (26/1/2021) Laser turn-on and modulation response. Laser Material Processing . 10 (29/1/2021) Optical injection, . 4 (22/12/2020) High power laser optical feedback, polarization. sources and performance improving novel trends . 11 (2/2/2021) Students’ . 5 (12/1/2021) Laser-based presentations. material macro processing. 12 (5/2/2021) Students’ . 6 (15/1/2020) Laser-based presentations. material micro processing. 9/2/2021: Exam Lecturers: C. Masoller, M. Botey 2 Learning objectives . Understand the physics of semiconductor materials and the electron-hole recombination mechanisms that lead to the emission of light. Learn about the operation principles of light emitting diodes (LEDs) and semiconductor optical amplifiers (SOAs). Become familiar with the operation principles and characteristics of laser diodes (LDs). 3 Outline: Semiconductor light sources . Introduction . Light-matter interactions in semiconductor materials . Light Emitting Diodes (LEDs) . Semiconductor optical amplifiers (SOAs) . Laser diodes (LDs) The start of the laser diode story: the invention of the transistor Nobel Prize in Physics 1956 “For their research on semiconductors and their discovery of the transistor effect”. The invention of the transistor in 1947 lead to the development of the semiconductor industry (microchips, computers and LEDs –initially only green, yellow and red). -
Leds As Single-Photon Avalanche Photodiodes by Jonathan Newport, American University
LEDs as Single-Photon Avalanche Photodiodes by Jonathan Newport, American University Lab Objectives: Use a photon detector to illustrate properties of random counting experiments. Use limiting probability distributions to perform statistical analysis on a physical system. Plot histograms. Condition a detector’s signal for further electronic processing. Use a breadboard, power supply and oscilloscope to construct a circuit and make measurements. Learn about semiconductor device physics. Reading: Taylor 3.2 – The Square-Root Rule for a Counting Experiment pp. 48-49 Taylor 5.1-5.3 – Histograms and the Normal Distribution pp. 121-135 Taylor Ch. 11 – The Poisson Distribution pp. 245-254 Taylor Problem 5.6 – The Exponential Distribution p. 155 Experiment #1: Lighting an LED A Light-Emitting Diode is a non-linear circuit element that can produce a controlled amount of light. The AND113R datasheet shows that the luminous intensity is proportional to the current flowing through the LED. As illustrated in the IV curve shown below, the current flowing through the diode is in turn proportional to the voltage across the diode. Diodes behave like a one-way valve for current. When the voltage on the Anode is more positive than the voltage on the Cathode, then the diode is said to be in Forward Bias. As the voltage across the diode increases, the current through the diode increases dramatically. The heat generated by this current can easily destroy the device. It is therefore wise to install a current-limiting resistor in series with the diode to prevent thermal runaway. When the voltage on the Cathode is more positive than the voltage on the Anode, the diode is said to be in Reverse Bias. -
Operating the Pulsed Laser Diode SPL LL90 3 Application Note
Operating the Pulsed Laser Diode SPL LL90_3 Application Note Introduction Optical peak power The SPL LL90_3 is a hybrid laser module. As shown in figure 2 the peak current and Additional to the laser chip the module therefore optical peak power is adjusted by contains two capacitors and a MOSFET the applied charge voltage. The SPL LL90_3 which act as a driver stage. The two typically delivers 70 W at 18.5 V (30 ns, 1 capacitors are connected in parallel to sum kHz). their individual capacitance of 47 nF. The The maximum rating of peak power is 80 W. emission wavelength is 905 nm. The By increasing of pulse repetition frequency specified optical peak power is 70 W. the peak optical power will be slightly decreased (as shown in fig 2). Principal of operation The capacitors are charged using a constant DC voltage. Each time the gate of the MOSFET is triggered, the capacitors are discharged via the laser chip leading to a short and high-amp current pulse. These high-amp current pulses are required to obtain the high peak power laser emission (at charge voltage of 18.5V a current pulse of up to 30A is possible) The pin configuration of the SPL LL90_3 laser diode is as follows: Pin 1: Trigger signal for the MOSFET gate Pin 2: Charge voltage Pin 3: Ground Figure 1: Hybrid pulsed laser diode SPL Variation of optical peak power LL90_3 with integrated driver stage. Figure 2: with charge voltage (pulse width 30 ns, PRF 1 kHz and 25kHz, gate voltage 15 V) for SPL LL90_3 using the MOSFET driver 3 Elantec EL7104C. -
VCSEL Pulse Driver Designs for Tof Applications
Vixar Application Note VCSEL Pulse Driver Designs for ToF Applications 1 Introduction ............................................................................................................................. 2 2 Design Theory ......................................................................................................................... 2 2.1 Schematic Components .................................................................................................... 2 2.2 Design Inductance ............................................................................................................ 3 2.3 Rise and Fall Time ........................................................................................................... 5 2.4 Timing Delay.................................................................................................................... 5 3 Low Power Driver Design ...................................................................................................... 5 4 High Power Driver Design...................................................................................................... 7 4.1 GaN FETs ......................................................................................................................... 7 4.2 Gate Drivers ..................................................................................................................... 7 5 VCSEL Performance .............................................................................................................. 8 6 Conclusions -
Speed of Light with Nanosecond Pulsed 650 Nm Diode Laser M
Speed of Light with Nanosecond Pulsed 650 nm Diode Laser M. Gallant May 23, 2008 The speed of light has been measured many different ways using many ingenious methods. The following note describes a method which is conceptually very easy to understand and fairly easy to implement. The technique is the simple time-of-flight optical pulse delay method using a fairly short (nanosecond) optical pulse and an oscilloscope with bandwidth between 50 - 100 MHz. THE LASER Common low power laser pointers, typically emit at a wavelength of 650 nm and operate from two to four 1.5 V button cells. Many of these lasers can be easily extracted from the pointer assembly and pulse-modulated to several hundred megahertz. The laser used here was removed from a low power (< 5mW) laser pointer assembly from a popular retail outlet. GENERATION OF SHORT OPTICAL PULSES The laser is prebiased below threshold, at 5 - 10 mA current (threshold current for the laser used here is 24 mA) using an inductor as a bias insertion element. A short (< 5 ns) electrical pulse modulates the laser. Since a very low duty cycle is used for pulsing the laser, fairly high current pulses are possible without degrading the laser. The actual forward current and voltage achieved during the drive pulse are dependent on the details of the I-V characteristic of the specific laser used, but are typically in the range of 50 - 100 mA and 6 - 10 V respectively. The short electrical pulse is generated using a simple avalanche transistor circuit. Due to the high frequency content of the short pulse, the actual shape of the current pulse driving the laser will depend on the circuit components (series resistors etc.) and parasitic electrical effects (series inductance of connection wires etc.) The circuit has been described by Jim Williams in a Linear Technology Measurement and Control Circuit Collection and has many other uses. -
Bipolar Junction Transistor As a Detector for Measuring in Diagnostic X-Ray Beams
2013 International Nuclear Atlantic Conference - INAC 2013 Recife, PE, Brazil, November 24-29, 2013 ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN ISBN: 978-85-99141-05-2 BIPOLAR JUNCTION TRANSISTOR AS A DETECTOR FOR MEASURING IN DIAGNOSTIC X-RAY BEAMS Francisco A. Cavalcanti1,2, David S. Monte1,2, Aline N. Alves1,2, Fábio R. Barros2, Marcus A. P. Santos2, and Luiz A. P. Santos1,2 1 Departamento de Energia Nuclear Universidade Federal de Pernambuco Av. Prof. Luiz Freire, 1000 50740-540 Recife, PE [email protected] 2 Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE / CNEN) Av. Prof. Luiz Freire, 1 50740-540 Recife, PE [email protected] ABSTRACT Photodiode and phototransistor are the most frequently used devices for measuring ionizing radiation in medical applications. The cited devices have the operating principle well known, however the bipolar junction transistor (BJT) is not a typical device used as a detector for measuring some physical quantities for diagnostic radiation. In fact, a photodiode, for example, has an area about 10 mm square and a BJT has an area which can be more than 10 thousands times smaller. The purpose of this paper is to bring a new technique to estimate some physical quantities or parameters in diagnostic radiation; for example, peak kilovoltage (kVp), deep dose measurements. The methodology for each type of evaluation depends on the energy range of the radiation and the physical quantity or parameter to be measured. Actually, some characteristics of the incident radiation under the device can be correlated with the readout signal, which is a function of the electrical currents in the electrodes of the BJT: Collector, Base and Emitter. -
Designing Photodiode Amplifier Circuits with Opa128
® DESIGNING PHOTODIODE AMPLIFIER CIRCUITS WITH OPA128 The OPA128 ultra-low bias current operational amplifier RS achieves its 75fA maximum bias current without compro- mise. Using standard design techniques, serious perfor- I R C mance trade-offs were required which sacrificed overall P J J amplifier performance in order to reach femtoamp (fA = 10–15 A) bias currents. IP = photocurrent RJ = shunt resistance of diode junction CJ = junction capacitance UNIQUE DESIGN MINIMIZES R = series resistance PERFORMANCE TRADE-OFFS S FIGURE 1. Photodiode Equivalent Circuit. Small-geometry FETs have low bias current, of course, but FET size reduction reduces transconductance and increases noise dramatically, placing a serious restriction on perfor- Responsivity ≈ 109V/W 5pF mance when low bias current is achieved simply by making Bandwidth: DC to ≈ 30Hz input FETs extremely small. Unfortunately, larger geom- Offset Voltage ≈ ±485µV etries suffer from high gate-to-substrate isolation diode leak- HP 109Ω age (which is the major contribution to BIFET® amplifier 5082-4204 input bias current). Replacing the reverse-biased gate-to-substrate isolation di- 2 6 OPA128LM ode structure of BlFETs with dielectric isolation removes 3 this large leakage current component which, together with a 8 noise-free cascode circuit, special FET geometry, and ad- 109Ω vanced wafer processing, allows far higher Difet ® perfor- mance compared to BIFETs. FIGURE 2. High-Sensitivity Photodiode Amplifier. HOW TO IMPROVE PHOTODIODE AMPLIFIER PERFORMANCE An important electro-optical application of FET op amps is √ for photodiode amplifiers. The unequaled performance of eOUT = 4k TBR the OPA128 is well-suited for very high sensitivity detector k: Boltzman’s constant = 1.38 x 10–23 J/K ° designs. -
SDN136 Analog High Speed Optocoupler 1Mbd, Photodiode with Transistor Output
SDN136 Analog High Speed Optocoupler 1MBd, Photodiode with Transistor Output Description Features The SDN136 is a high speed optocoupler consisting of an TTL Compatible infrared GaAs LED optically coupled through a high High Bit Rate: 1Mb/s isolation barrier to an integrated high speed transistor and Bandwidth: 2.0MHz photodiode. Open Collector Output High Isolation Voltage (5000VRMS) Separate access to the photodiode and transistor allow High Common Mode Interference Immunity users to reduce base-collector capacitance, enabling much RoHS / Pb-Free / REACH Compliant higher switching speeds. Signals with frequencies of up to 2.0MHz can be switched, giving the SDN136 a much broader application range than traditional optocouplers. Agency Approvals The SDN136 comes standard in an 8 pin DIP package. UL / C-UL: File # E201932 Applications VDE: File # 40035191 (EN 60747-5-2) High Speed Logic Ground Isolation Replace Slower Speed Optocouplers Absolute Maximum Ratings Line Receivers Power Transistor Isolation Pulse Transformer Replacement The values indicated are absolute stress ratings. Functional Switch Mode Power Supplies operation of the device is not implied at these or any High Voltage Insulation conditions in excess of those defined in electrical Ground Isolation – Analog Signals characteristics section of this document. Exposure to absolute Maximum Ratings may cause permanent damage to the device and may adversely affect reliability. Schematic Diagram Storage Temperature …………………………..-55 to +125°C Operating Temperature …………………………-40 -
PLD-92 Laser Diode Datasheet
PLD-92 Series: 915-970 nm, 80 W Multi-mode Fiber-coupled Diode Lasers Features Amplifier Pumping Direct Diode Lasers 915, 940, 970 nm Center Wavelength Stabilization Laser Pumping Material Processing Wavelengths and Dichroic Options Graphic Arts / Printing Medical & Dental 80 W Output Power 0.15 NA into 110 μm Fiber Core Diameter Illumination Photovoltaics High Reliability Robust Compact Package IPG Photonics’ PLD-92 fiber-coupled diode lasers provide up to 80 W of output power within 0.15 NA. PLD-92 diode are provided with a 110 μm fiber core and center wavelengths at 915 nm, 940 nm or 970 nm. Wavelength stabilization and dichroic options are also available. IPG’s best-in-class diode technology offers an ideal combination of power, reliability and form factor. We manufacture to rigorous telecom-grade standards in the world’s largest high power diode fab. Each wafer is individually qualified, which sets IPG apart from alternative industrial pump products using short-lived diode bars and bar-stack technologies. PLD-92 diode lasers are preferred for fiber amplifier and laser pumping, material processing, and direct diode applications. PLD-92 Series: 915-970 nm, 80 W Multi-mode Fiber-coupled Diode Lasers Optical and Electrical Characteristics* PLD-92 Center Wavelength**, nm 971 Center Wavelength Tolerance, nm ± 5 Output Power, W 80 Spectral Width (FWHM), nm 4 Slope Efficiency, W/A 5 Minimum Efficiency, % 52 Threshold Current (ITH), A 0.8 Operating Current (IOP), A 16 Forward Voltage, V 9.3 Recommended Case Temperature, ⁰C 25 Wavelength Shift with Temperature, nm/⁰C 0.35 Wavelength Shift with Operating Current, nm/A 0.6 *Typical performance data measured at 16 A, 25⁰C.