High-throughput optical inter-board interconnects for next-generation on-board digital transparent processors N. Venet, M. Sotom, H. Gachon, Thales Alenia Space, France V. Foucal, M. Pez, D-Lightsys, France V. Heikkinen, VTT Finland T. Tuominen, Patria, Finland S. Pantoja, DAS Photonics, Spain 83230910-DOC-TAS-FR-001 ICSO 2014 -Tenerife October 9, 2014
Outline 2 Telecom satellite market trend Applications High throughput optical interconnect demonstrator Development of Key optoelectronic and optical components Integration and test of the optical interconnect breadboard Conclusions
Telecom satellite market trend 3 Increasing capacity payloads Higher number of beams Broader bandwidth More versatile solutions Grasp quickly new market Adapt to the evolutions over the 15 years of the satellite lifetime Flexible telecom payload able to provide high data rate as a means to achieve these goals
Applications 4 Thanks to Digital Transparent Processor (DTP) The core of a flexible payload Optimization of Resources of a given satellite Coverage flexibility Resources allocation flexibility Rx and Tx connectivity flexibility Channelization flexibility Other applications will be Digital Beam Former (DBF)
Applications 5 Digital Transparent Processor Channelization of input frequency bands Routing of each channel between beams DTP s feature Analogue to digital (ADC) at inputs Digital to analogue (DAC) at outputs Extensive use of digital processing Example of advanced DTP 100 I/O channels with 500Mhz bandwidth 1 TBps to be processed internally
High throughput optical interconnect demonstrator 6 Optical interconnect demonstrator based on a DTP 2G architecture 10 slices of 3 different types Rx/Tx slice ( 2 stacked ) Passive coupler slice (1 stacked) Dummy slices (7 stacked) an optical interconnection plane (2)
High throughput optical interconnect demonstrator 7 Rx/Tx slice hosting a Rx/Tx board with Multichannel Tx and Rx from D-Ligthsys Upgraded for space application Designed to support 12 x 10 Gbps Multichannel Tx/Rx from VTT Upgraded for space application Designed to support 4 x 10 Gbps for both Tx and Rx side Thermal resistors to simulate ASIC dissipation up to 80W Electrical interposer to interconnect optoelectronic modules to PCB High density, multi-fibre optical connectors based on MT ferrules Optical test in/out interfaces Electrical test interfaces
High throughput optical interconnect demonstrator 8 Tx/Rx slice view Optical connectors based on MT ferrules Electrical interposer Optoelectronic modules Electrical test interfaces Thermal resistors on the other side Optical in/out interface
High throughput optical interconnect demonstrator 9 Passive coupler slice hosting Optical coupler High density, multi-fibre optical connectors based on MT ferrules Optical test in/out interfaces Dummy slice hosting High density, multi-fibre optical connectors based on MT ferrules Optical test in/out interfaces
High throughput optical interconnect demonstrator 10 Coupler slice view Optical connectors based on MT ferrules Optical in/out interface Optical coupler
High throughput optical interconnect demonstrator 11 Optical interconnect plane 2 optical flexes fixed on a metal plate 50µ/125µm Graded-index optical fibre Terminated by multi-fibre optical connectors based on MT ferrules
Development of key optoelectronic and optical components 12 Optoelectronic modules Support up to 10 Gbps per channel over MM fibre ribbon Incorporate state of the art 850nm GaAs VSCEL array and/or GaAs PIN photodiode array VTT transceiver Packaged in small-size hermetic ceramic package (17mm x 17mm) Low power consumption less than 10mW/ Gbps per channel MT ferrules/mpo connector D-Lightsys Tx or Rx
Development of key optoelectronic and optical components 13 Optical coupler Ruggedized, small and lightweight package Array of 12 individual passive 1x2 optical splitters Equipped with MPO male optical connector DAS Photonics coupler
Development of key optoelectronic and optical components 14 Component test sequence Optoelectronic modules Passive coupler module
Development of key optoelectronic and optical components 15 Optoelectronic module test result (as an example) Eye diagrams after 1002 hours ageing at 125 C Manufacturer A s module under 10Gbps PRBS modulation Manufacturer B s module under 7Gbps PRBS modulation
Development of key optoelectronic and optical components 16 Coupler module test result (as an example) Insertion loss of the passive module after TID testing (50 Krad)
Integration and test of the optical interconnect breadboard 17 Integration of the breadboard Each slice stacked and screwed to its neighbor Optical interconnect plane mounted on top
Integration and test of the optical interconnect breadboard 18 Environmental conditions of the tests First at ambient temperature and at atmospheric pressure Then in thermal vacuum chamber at 25 C, +70 C and -30 C In thermal chamber at atmospheric pressure same range of temperature And after vibrations (same conditions as for a digital processor EQM) Thermal vacuum chamber Vibrations
Integration and test of the optical interconnect breadboard 19 Test results of the breadboard In thermal vacuum BER of 10-12 achieved at up to 3.25 Gbps At 6.5 Gbps, performance limited by long cables In thermal chamber Better results as less disturbances (2m cables instead of 4 m) At hot and ambient temperatures, BER of 10-12 at 6.5 Gbps for manufacturer A and at 5.2 Gbps for manufacturer B At cold temperature, BER of 10-12 After vibrations all channels working nominally at 25 C at 3.25 Gbps for both manufacturer BER of 10-12 at 6.5 Gbps, for manufacturer A s channels and for most of manufacturer B s channels No deviation larger than 0.8 db for optical interconnect losses
Integration and test of the optical interconnect breadboard 20 Eye diagram examples at 70 C in thermal chamber at 25 c after vibration Manufacturer A s module Manufacturer B s module Manufacturer A s module Manufacturer B s module
Conclusions 21 An optical interconnect breadboard was developed using multichannel Tx/Rx designed for operating at up to 10 Gbps per channel, thus supporting an aggregate data rate of 40-120 Gbps and an optical flex to route the signals from Tx to Rx boards This optical interconnect breadboard is scalable to one thousand optical fibre links and to an overall throughput in excess of 1 Terabit/s The functional and thermal testing have shown that the performance of the optoelectronic and passive modules are close to target specifications No degradation during the testing after vibration proving that the optical interconnect breadboard was quite robust Potential improvements have been identified The results of the test campaign provides higher confidence in the introduction of optical interconnect technology in future highly-demanding onboard digital processors
Acknowledgements 22 This work was carried out in the frame of the Artes 5 ESTEC contract «Optical Inter-Board Interconnects for High Throughput on-board Processors» The authors are grateful to ESA the European Space Agency, to CNES the French National Space Agency, as well as the Finish and the Spain national space agencies for their support. The authors also thank Nikos Karafolas as a Technical Officer for having initiated and stimulated this activity.