Multi-gigabit intra-satellite interconnects employing multi-core fibers and optical engines

Transcription

1 VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD at ICSO conference 19 Oct 2016 Multi-gigabit intra-satellite interconnects employing multi-core fibers and optical engines Mikko Karppinen et al. VTT P. Westbergh, J. Gustavsson, A. Larsson Chalmers Univ. Rashid Safaisini Philips Minsu Ko, Dietmar Kissinger IHP Lars Grüner-Nielsen OFS Michel Sotom, Norbert Venet Thales Alenia Space L. Stampoulidis, J. Edmunds, E. Kehayas Gooch & Housego

2 Results from ongoing project: Multi-Gigabit, Scalable & Energy Efficient on-board Digital Processors Employing Multicore, Vertical, Embedded Optoelectronic Engines Photo: ESA Developing ruggedized optical interconnects for future terabit-scale telecom satellites Optics needed for on-board processors, thanks to: Savings in mass, volume, power dissipation Better signal integrity and reduced EMI Beyond state-of-the-art interconnect performance in space: Record bit-rate density (25 Gbps/channel, 150 Gbps/fiber) Record power efficiency, and temperature range EU FP7 Space research project grant for Project partners: Coordinator: Leontios Stampoulidis / Gooch & Housego 2

3 Device technologies and performance Transmitter and receiver optical engines integrating: Novel 6-core Multimode Multicore Fibers 850-nm circular VCSEL & PD arrays, layout matched to MCF Multi-channel Driver & Receiver ICs, matched to VCSEL & PD arrays All devices optimized for harsh environment, esp. space compatibility: Wide temperature range (operation >100 C) High reliability, long life Radiation hardened Bit rates per channel: (10 ) 25 Gb/s and beyond => Aggregate per fiber 150 Gb/s (= 6 x 25 Gb/s) Ch5 Ch6 Ch1 Ch2 Ch4 Ch3 6-channel VCSEL array 6-core multimode fiber 6-channel PD array 3

4 Motivation Why Multicore Fiber Need for ever higher interconnect capacity and density in computing & communications equipment Multicore fiber (MCF) enables a parallel optic link in a single fiber Multiplies interconnection density of standard 250µm-pitch fiber ribbon cable Hermetic feedthroughs easier and more robust than with fiber ribbons Can use single fiber connectors already space-qualified (instead of ribbon connectors) Multimode multicore fiber is compatible with 850-nm VCSEL technology => many advantages for very-short-reach interconnects, e.g. cost and power efficiency 125 µm 6-core multimode fiber 4

5 Transceiver module packaging Small hermetic transceiver modules: Based on robust metal-ceramic integration and packaging platform, proven e.g. in VTT s other space-grade transceivers Mid-board module for integration next to ASICs on PCB, with >25 Gbps/ch electronic I/O Two multicore fiber pigtails (transmit + receive), hermetic For wide ambient temperature range: operation 40 up to +100 C (uncooled, without micro-controller) storage C and beyond Former Ruggedized Transceivers (by VTT) - based on 50µm multimode fibers and VCSELs Next Gen SpaceFibre duplex transceiver, 6.25 Gb/s 4+4 x 10 Gb/s transceiver with ribbon fiber pigtail 150 Gb/s MCF Transceiver - using custom active devices 5

6 Radiation-hard Multimode Multicore Fibre (by OFS) Refractive index profile Cross-section Target design: GeO 2 -doped only graded index core Core diameter: 26 µm NA: 0.20 core to core pitch: 39 µm Cladding diameter: 125 µm Coating diameter: 245 µm Measured bandwidth and attenuation of 500 m of multicore cable 850 nm 850 nm Fiber # MHz km db/km Average

7 Radiation-hard Multimode Multicore Cable (by OFS) Coating Material Dual Layer Acrylate Coating Diameter 245 µm Cladding Diameter 125 µm Outer Cable Diameter 0.8 ± 0.05 mm Outer Jacket Material High Temperature ETFE Strength Member Braided Aramid Yarn Cable Weight 0.75 kg/km Minimum Bend Radius Installation 12 mm Minimum Bend Radius Long Term Maximum Installation Tensile Load 8 mm 100 N Maximum Operating Tensile Load 38 N Operating Temperature -40 to +100 C Storage Temperature -55 to +125 C Vacuum mass lost tests with multicore cable (ECSS Q ST 70 02C standard; at 125 C for 24 h) Collected volatile condensable material: mean 0.04 % Within acceptance limits 7

8 VCSELs for MCF link (by Chalmers) 6-channel VCSEL array matched to MCF geometry (for easy coupling) Demonstrated: up to C, and 85 C Ch6 Ch5 Ch4 Ch5 Ch6 Ch4 Ch1 Ch2 Ch3 Ch1 Ch2 Ch3 8

9 Photodiodes for MCF links (by Philips) PD arrays optimized for multicore layout, up to 25 Gbps, and high temp Dark current: < C, and <1 100 C (@ -2V bias) 3 db bandwidth ~22 GHz (@ -2V) Responsivities ~0.5 A/W Ch6 Ch5 Ch4 Ch1 Ch2 Ch3 Frequency response of a selected channel of a typical PD array (24µm diameter aperture) 9

10 Driver and receiver ICs (by IHP) 3-channel Driver and TIA ASICs optimized for the VCSEL & PD arrays IHP s SiGe BiCMOS technology (rad-hard) Power dissipation ~5 mw/gbps (Tx+Rx); Designed for operation up to 120 C 1 st generation devices: Driver demonstrated up to 40 Gb/s; TIA up to 25 Gb/s < vs. Data Rate > 12.5 Gb/s < vs. > Low 6.25 Gb/s 25 Gb/s Mid 12.5 Gb/s Driver 40 Gb/s High 25 Gb/s TIA 2 nd generation ICs include also channel-independent digital controls Recently fabricated; performance confirmed up to 25 G so far 10

11 Transceiver Modules (by VTT) Electrical interposer (space-grade) Hermetic fiber feedthroughs TOSA and ROSA (6 x 25 Gbps) Multicore fiber pigtails Transceiver Module on Evaluation Board (photo without clamp mechanism for visual purpose) Excellent thermal management: Chip vs. PCB temperatures: ICs ~+5 C, VCSEL ~+3 C Status: Environmental tests are starting 11

12 Data transmission results: Transmitter Transmitter eye diagrams (at RT, using 1 st 40Gbps BER curves (sensitivity limited by receiving equipment) 12

13 Data transmission results: Receiver Receiver eye diagrams (at RT, using 1 st Gen TIA) 13

14 Conclusion and Outlook Ruggedized optical transceivers for multi-gigabit data links: Based on novel rad-hard multimode multicore fibers Multicore-optimized 850-nm VCSEL/PD arrays Rad-hard multi-channel ASICs Fully hermetic transceiver module packaging Very wide operation temperature range Optical engines demonstrated >25 Gbps/ch i.e. >150 Gbps/fiber Manufacturing and testing of complete transceiver modules is ongoing Future opportunity: co-package optical engines with processor ASICs Developed for harsh environment intra-satellite applications. But technology well applicable also for other applications, e.g. low power and high-temp operation allow savings in cooling in datacenters 14

15 Acknowledgement This research was supported by European Union 7th Framework Programme under Grant no

16 Thank you! For further information please contact: Mikko Karppinen, D.Sc. Senior Scientist Photonics Integration VTT Ltd Kaitoväylä 1, P.O. Box 1100 FI Oulu, Finland tel (direct/mobile) 16

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