1060nm VCSEL --based 10Gbps optical interconnects
Hideyuki Nasu
FITEL Photonics Laboratory Furukawa Electric Co., Ltd.
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 Outline
Background Why we need optical interconnects? Trends in optical interconnects Advantage of 1-µm optical interconnect InGaAs VCSEL and PD Low power consumption Higher modulation capability Link budget 10-Gbps x 12-ch1060-nm parallel-optical module Performance data Future prospect
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 2 Performance trend (Super computer & Computer)
Fujitsu “Kei” is No. 1 now, but no There is correlation between computer optical link performance and bandwidth.
(FLOPS) Next next next plan
100 250 (bps/machine) Peta T
Next next plan 10PFLOPS
1 2.5 Peta T Next generation plan 360TFLOPS Computer for Earth simulator 10 plan company 25 Tera G
Supercomputer 100 Renewal of 250 Giga conventional M computer Personal computer Computer for research
1995 2000 2005 2010 2015 2020 2025 PSI symposium 2005 : Ministry of Education, Culture, Sports, Science and Technology H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 3 Bandwidth trend of Backplane (Edge Router)
There will be high possibility of accelerating time plan in consideration for power consumption.
Electrical backplane
Optical backplane High speed interface (commercial base) Router backplane band width width bandband backplanebackplane Router Router
New standard boost traffic and NW 100GbE standardized equipment bandwidth. NEDO’s project : Next generation High performance Network Device
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 4 Data rate trend in server systems
Forecast for server connection speed, supplied by Intel and Broadcom, indicates the migration from 1 to 10, then to 40 and 100 Gbit/s transmission is at hand
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 5 Power consumption in IT equipment Power consumption trends ： Japan 5 times, from 2006 to 2025 ⇒ CO2 emission-increase Worldwide ： 9 times, from 2006 to 2025
Power consumption estimation Environmental issue (Japan)（日本）
12X Green IT Project (Japan) •Power reduction target •Data center: ≥ 30 ％
TV • NW router: ≥ 30 ％ 5X Server NW Equipment International project •WSC / GAMS •Climate Savers •The Green Grid Driving forward activities for power saving
Ministry of Economics, Trade and Industry, Green IT Project H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 6 I/O power trend
Power trend on optical and electrical inter face
△ Commercial × Sample
)) ○ Research Power saving in optical transmission
Gbps (Photonic integration) Power saving in electrical transmission (Low voltage driving) Electrical Electrical Electrical
Furukawa Electric
Power consumption (W/ (W/ consumptionconsumption Power Power 7mW/Gbps (10Gbps x 12ch) year
Expectation and future perspective on optical interconnect (Technical roadmap of optical circuit packaging technology), p. 7 2010
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 7 Trend of Optical interconnection
LSI
2020 Optical circuit board Opt connector
Optical printed board Optical waveguide Optical Fiber Optical Module LSI Opt connector
Opt connector 2012 Optical Fiber
Back plane
LSI Optical Transceiver
Now Conventional optical interconnection
Optical module will be expected more small and high speed. Connector will be more high density.
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 8 How dose electrical transmission distance affect to optical signal performance? Input Input Optical engine
RX output: Eye opening 400mm MSL=0mm MSL=400mm no PE PE3
Eye opening at BER10 -12
Eye opening and Power increase rate •10Gbps, NRZ 250 PE1 PE2 PE3 70 •12ch simultaneous operation 60 200 50 150 40 Minimizing electrical connection between optical 100 30 20 engine and LSI growth growth growth raterate (%) (%)
Eye opening(mV) opening(mV) Eye Eye 50
10 consumption consumption Power Power
0 0 (%) (%) raterate increaseincrease Power Power 0 100 200 300 400 500 no PE Powe r saving MSL length(mm) Power H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 9 Requirements on optical interconnect
Low power consumption xx mW/Gbps High capacity High speed, 10Gbps, 14Gbps, 25Gbps Number of multiplexed signals Longer transmission link Covering the length of <300m Very long distance in Enterprise: ~1km Low cost $xx/Gbps $xx/m^2 Higher reliability Huge number of modules
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 10 Advantages of 1 µm optical devices InGaAs QW VCSEL High High speed High differential power gain Wide bandwidth Low power Low band gap Low driving energy voltage
SPIE Proceedings, vol. 4649, pp.19-24, 2002. Low current Inhibiting Al oxidization Al free High reliability density
EBIC image after aging test Slow DLD
Inhibiting DLD by Indium GaAs SQW InGaAs SQW PTL, vol. 2, no. 8, 1990 InGaAs PIN-PD High sensitivity Low power drive of VCSEL 25% increase compared with 850nm GaAs PD
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 11 Power saving ability in TX Low power operation of 1060-nm InGaAs QW VCSEL Clear eye openings Error free transmission
Vpp I = 1.8 mA (mV) 150
230
A bias current of 1.8mA is sufficient for 10Gbps operation
J. B. Herou et. al, CLEO/QELS 2010, CWP3.
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 12 Low power operation by 1060nm VCSEL 1060nm VCSEL
S. Nakagawa, FOE-12, Photonix2011, Apr. 2011
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 13 Reliability of 1060nm VCSEL
K. Takaki et.al, Photonic West. Jan. 2011 S. Nakagawa, FOE-12, Fiber Optics Expo, Apr. 2011
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 14 Power saving ability in TX
TX power vs. VCSEL bias current Power consumption in TX TX モジュールの消費電力 8.0 25˚C 850nm VCSEL 7.0 80˚C 6.0
5.0 1060-nm VCSEL 4.0
3.0
2.0
1.0
Power consumption (mW/Gbps) (mW/Gbps) consumption consumption Power Power 0.0 0 2 4 6 8 10 VCSEL bias current (mA)
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 15 Higher modulation capability 40Gbit/s direct modulation
NEC group
T. Anan et. al. International Symposium on VCSELs and Integrated Photonics, E-3, 2007 20Gbit/s parallel-optical module •12ch Transceiver •20Gbit/s, PRBS 2 7-1 •50m of GI50 MMF •Error free transmission •Minimum sensitivity: <-8.6dB at 10 -12 •Crosstalk penalty: 4dB
K. Kurata, OFC2010, OThS3. K. Yashilki et. al., ICSJ2010, 19-3
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 16 1µm VCSEL (TU Berlin) 980nm VCSEL
A. Mutig, OIDA Workshop, Apr. 2011 H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 17 Advantages of 1 µm optical link Parameters Items Parameters 1060nm 850nm RX: 0.75A/W 0.6A/W PD Sensitivity InGaAs GaAs Transmission loss 0.95dB/km 2.09dB/km Fiber optics Chromatic dispersion -34.2ps/nm/km -90.42ps/nm/km TX: Maximum output +1.5dBm -2.2dBm Eye safety power Class 1 Class 1 *1. IEC60925-1 2001, eye-safety class1. Condition:Fiberbandwidth=5000MHz.km Measured (1060nm) OM3 5 Bit rate: 10Gbps (dB) 5 Calculation (1060nm) 2000MHz·km Calculation (850nm) 4 OM2 4 penalty penalty 33
22 500MHz·km 11 Longer distance 850nm 1060nm 1300nm 00 Increase of power 300 600 900 1200 0 Conventional OM2 applicable Low cost Transmission distance (m) H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 18 Fiber transmission Conventional OM-2 and OM-3 MMFs 1060-nm optimized MMF
Received power (dBm) Received power (dBm) Received power (dBm)
OM2: OM3: 1060-nm MMF Penalty <2dB up to 300m Penalty ~4dB at 300m Penalty ~3dB at 1000m Max. 300m recommendation Max. 150m recommendation Potential 300m or beyond
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 19 Modal bandwidth Power penalty as a function of transmission distance Bit rate: 10Gbps Calculated by IEEE 802.3z link model spread sheet Limited laser modes (1060-nm VCSEL) Modal bandwidth is measured with frequency sweeping method
6 OM2 OM3 Modal bandwidth 1060nm MMF 5 OM-2 simulation Modal bandwidth (MHz×km) OM-3 simulation MMF type (1) (2) (1) 1060nm MMF simulation 850 nm 1060 nm 1300 nm 4 2262 (OFL) OM-2 790 1602 2612 (LLM) 3 1094 (OFL) OM-3 4509 708 1741 (LLM) 4318 (OFL) 2 1060-nm MMF - - PowerPower penaltypenalty (dB) (dB) 5433 (LLM)
1 OFL: Overfilled launch LLM: Limited laser modes 0 Note 1: Fiber bandwidth is calculated from DMD data 0 200 400 600 800 1000 Note 2: Measured by frequency sweeping method Transmission distance (m) JIS C 6824, Aug. 1997.
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 20 25Gbps optical link Power penalty as a function of transmission distance Bit rate: 25Gbps Receiver bandwidth: 18.75GHz MMF bandwidth: 4700MHz.km (OM4 level) Tr/Tf(20% -80%)=16ps Spectral linewidth: 0.45nm, 0.65nm Calculated by IEEE 802.3z link model spread sheet
6 100m 300m 1060nm 5 850nm 4
3
0.45nm 850nm 2
PowerPowerpenaltypenalty(dB) (dB) 0.45nm 1060nm 0.65nm 850nm 1 0.65nm 1060nm
0 0 0.1 0.2 0.3 0.4 Transmission distance (km)
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 21 Scalability to the future Coarse wavelength division multiplexing (CWDM) Capability of selecting lasing wavelength Cost reduction? Wide range of wavelength sensitivity MAUI project: parallel multiwavelength optical subassemblies (PMOSAs)
6.6mW/Gbit/s: 10.42Gbit/s x 48ch LEOS2005, TuW1, Mar. 2005, JLT vol. 22, no. 9, p.2043 2004, ECTC, p.1027 2005. H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 22 Scalability to the future 1060nm Attenuation in polymer waveguides 5000 PMMA base Poly (methyl methacrylate) (PMMA) 4500 4000 Not available PD polymer base 3500 PF polymer base Perdeuterated (PD) polymer 3000 Available 2500 Perfluorinated (PF) polymer 2000 Available 1500 VCSEL 1000 500 Lens Polymer waveguide 0 PCB 0.5 0.6 0.7 0.8 0.91.0 1.1 1.2 1.3 1.4 Wavelength (µ m) Applied to silicon photonics T. Ishigure et. al, Science and Technology of Polymer and Advanced Materials, Plenum Press, New York, 1998 1060nm is in the transmittance window of Silicon
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 23 10Gbit/s x 12ch optical engine Optical pluggable and pigtailed engines 90º-angled connector Pigtailed Heat sink Optical pluggable
Module 13X13Xt3.4mm Pluggable socket Module BW > 10GHz
21mm 21.7mm
0 0
Pluggable socket -1 -10
-2 -20 18mm 18mm S11 (dB) S11 S21 (dB) S21 -3 -30
-4 -40 S21 S11 -5 -50 0 2 4 6 8 10 Frequecncy (GHz) H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 24 12.5Gbit/s x 12ch x 4 High-density optical pluggable solution 600Gbps mezzanine card
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 25 Parallel-optical engines
10Gbps × 12ch parallel-optical engine 1060-nm VCSEL array ，InGaAs PD array Heat sink BiCMOS LDD/TIA Electrical interface: pluggable socket Capability of replacing optical modules Wide band width >10GHz Mechanical size: Module Module: 13 × 13 × 3.4 mm (not to include pigtailed fiber) Socket: 21.7 × 21 × 13.7 mm 21mm 21.7mm Performance Pluggable socket: Power consumption ：：： <10mW/Gbps BW > 10GHz Operating case temperature 0~70 °C Transmission ： 120Gbps error free
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 26 Module structure Thermal dissipation Schematic view Microlens VD/TIA 12-ch fiber ribbon Metal cover
MT ferrule
Multi-layer ceramic 12ch VCSEL/PD array RF path 92 LGA substrate Differential transmission lines 0 0
-5 S-parameter (EM simulation) -3 -10
-15
-6 -20 SDD21: >-3dB at 0-10GHz -25 -9 -30 SDD11(dB) SDD11(dB) >-5dB at 0-20GHz SDD21(dB) SDD21(dB) DB(|S(2,1)|) : Spara_ESA SDD11: <-15dB at 0-20GHz -35 -12 DB(|S(1,1)|) : Spara_ESA -40
-45
-15 -50 0 5 10 15 20 Frequency(GHz) H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 27 Electrical-pluggable interface Capability of module replacement System maintenance Repeatability of module installation
Wide bandwidth: >10GHz S-parameters 0 0 Cross sectional drawing -1 -10 Parallel-optical module
-2 -20 S11(dB) S21(dB) -3 -30
-4 -40 S21 Spring pin S11 -5 -50 Electrical pluggable socket 0 2 4 6 8 10 Frequecncy (GHz)
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 28 Eye diagrams
TX output and RX output
15 °C 25 °C 50 °C 80 °C TX output
RX output
Monitor channel: Ch 7 Case temperature: 25~80 °C Bias current: 4mA, Optical power: -4.0dBm, Extinction ratio : 4.5dB Tr/Tf: (TX output) 31.6ps/47.2ps, (RX output) 36.0ps/37.6ps
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 29 BER performance BER measurement 10Gbps × 12ch simultaneous transmission Over operating case temperature (Back to back) Transmission in MMF of 300m
80 ℃ Back to back 50 ℃ 10 -4 25 ℃ 10 -4 300m 15 ℃
10 -6 10 -6 BER BER
10 -8 10 -8
10 -10 10 -10
-12 10 -12 10 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 -18 -16 -14 -12 -10 -8 -6 Received optical power(dBm) Received optical power (dBm) Minimum sensitivity at 25 °C: -10.2dBm Power penalty: 0.6dB
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 30 Optical link power 1060nm 12ch x 10.315Gbit/s optical link Tc=25 °C: 5.9mW/Gbit/s Minimum sensitivity: <-12dBm BER=10 12 Tc=70 °C: 6.4 mW/Gbit/s 6.4mW/ Gbit /s -10 8 5.9mW/Gbit/s ch1 -11 7 ch2 ch3 -12 6 ch4 -13 5 ch5
-14 4 ch6 ch7 -15 3 ch8
-16 2 ch9 ch10
Sensitivity(dBm) Sensitivity(dBm) -17 1 ch11 -18 0 ch12 0 20 40 60 80 average Power consumption(mW/Gbps) consumption(mW/Gbps) Power Power Case temprature(deg.C) PC
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 31 Summary Technical trends in data centers and optical interconnects are described. Advantages of 1-µm optical inter connects Low power consumption Higher modulation capability Longer transmission distance Low cost solution with conventional OM-2 fibers High reliability with InGaAs devices Expansivity of 1-µm optical inter connects Usage of polymer waveguide Silicon photonics Coarse wavelength division multiplexing (CWDM) 10-Gbps x 12-channel 1060-nm parallel-optical modules Size: 13mm x 13mm x 3.4 mm Very Low power: <7mW/Gbps (Tc: 15 °C to 80 °C) Electrical-pluggable socket interface Very low power 7.0mW/Gbps over operating case temperature
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 32 Future perspective Higher speed >25Gbps High speed devices VCSEL, PD, CMOS (Silicon) Photonics Argument on wavelength: expectation on 1 µm wavelength Electrical wiring ： Wideband wiring, Crosstalk suppression Bandwidth control ： Equalization, Emphasis
Optical waveguide Terabus Project Polymer waveguide Loss, Bandwidth Optical coupling MMF ECOC2010, Tu4G3, Sept. 2010. Bandwidth (Refractive index profile, Core diameter) High-density Small optical engine 3D integration, CMOS Photonics Mounting technology Electrical pluggable Permanent mounting ECOC2010, Tu4G3, Sept. 2010. H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 33 Thank you!
H. Nasu/FITEL Phonics Laboratory, Furukawa Electric Co, Ltd. Technical seminar at CERN, Sept. 23 2011 34