PROJECT FINAL REPORT
Project acronym: SEPIANet
Project title: System Embedded Photonics in Access Networks
Project duration: 2 years 6 months from July 2011 to December 2013
Coordinator (organisation): Xyratex Technology Ltd
Scientific representative of the coordinator (name and title): Richard Pitwon
E-mail: richard_pitwon@xyratex.com
Project website address: www.SEPIANet.eu
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Final publishable summary report
Executive summary
The 2.5 year project aimed to develop optical backplanes for data storage systems for Cloud
& high performance computing, to enable increased energy efficiency and bandwidth in
excess of 20Gb/s. It was a vertically integrated consortium comprising Xyratex (Coordinator,
UK), ILFA (DE), Fraunhofer IZM (DE), TerOpta (UK), V-I Systems (DE) and Conjunct (UK).
It addressed the substantial challenges associated of developing a new optical PCB
technology, culminating in the successful demonstration of 3 fully integrated planar glass
waveguide optical backplane and pluggable connector platforms driven by system embedded
850 nm and external 1310 nm optical transceivers technologies, and validated them for both
in-system and system-to-system connectivity. Overall this was a very innovative project with a
good, vertically integrated team and there are good prospects for industrial exploitation.
Summary of project context and objectives
Bandwidth densities driven by interconnect speeds and scalable I/O within ICT systems,
including access network systems, data centre and server subsystems, will continue to
increase over the coming years thereby severely impacting cost and performance of future
data communication systems.
The project aim was to develop technology solutions for embedded optical architectures in
access network head-end systems to allow significant reduction in power consumption,
increased energy efficiency, system density and bandwidth scalability, which is currently
unfeasible in today’s copper driven access network systems.
The SEPIANet consortium drew on combined expertise in access network system design
(TerOpta, UK), glass optical waveguide fabrication (Fraunhofer IZM, DE), printed circuit board
fabrication (ILFA, DE), optical PCB interconnect solutions (Xyratex, UK), integrated optical
transceiver solutions (Conjunct, UK) and high speed VCSEL fabrication (V-I Systems, DE) to
develop a complete eco-system of embedded optical interconnect technologies operating
within the 1300 nm and 850 nm windows for multimode planar glass waveguide electrooptical PCBs (EOCBs).
Description of the main S&T results/foregrounds
The project started on 1st July 2011 and concluded in January 2014. During its 2.5 year
duration, the SEPIANet project consortium has tackled the substantial challenges associated
with bringing to fruition a disruptive new optical PCB technology and supporting eco-system.
These efforts culminated in the successful demonstration of 3 fully integrated planar glass
waveguide optical backplane and pluggable connector platforms driven by system embedded
and external 850 nm and 1310 nm optical transceiver technologies and validated for both insystem and system-to-system optical connectivity.
As coordinators of the project, Xyratex focused on establishing a team approach from all
partners and was highly successful in promoting a productive collaborative work environment
and forging ongoing collaborative relationships. The work was divided into work packages
with results as follows:
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System Design Study
TerOpta provided the technical input from a systems requirements viewpoint, and gathered
further information, improving the consortium’s knowledge capability within the field of optical
interconnect. Design aspects covered high speed analogue, digital and photonics-level
processing and all aspects of telecoms systems.
Thin Glass Waveguide Technology
Fraunhofer IZM successfully developed and deployed a disruptive new method of multimode
waveguide fabrication scaled to a large PCB form factor based on thin glass foil embedded
planar glass waveguides. IZM also developed a sophisticated active and partially automated
assembly process for aligning and attaching connectors to the glass waveguide interfaces in
the optical circuit board. These were successfully deployed on the electro-optical circuit
boards in the final demonstration platform.
Electro-optical Printed Circuit Boards
ILFA developed and successfully deployed a novel cold lamination process to embed the
glass waveguide foils into a multilayer copper PCB stack-up, mechanically pre-structured by
the hybrid laser system thus paving the way to fast and reliable manufacturing capabilities of
glass substrate electro-optical backplanes. The expertise and product know-how developed
by ILFA during the SEPIANet project has enabled them to become one of the first commercial
PCB foundries in the world offering glass-based optical PCB products, thus securing new
business and increasing their global customer base for future commercial products.
Pluggable Optical PCB Connectors
Xyratex successfully designed and developed a full suite of passive optical connector
components to, for the first time, enable pluggable optical connectivity to a glass waveguide
based electro-optical backplane at both board-to-board and system-to-system levels.
High Speed 1310 nm VCSEL Technology
VI Systems was responsible for the design, packaging and testing of long wavelength high
speed VCSEL structures and modules. 10Gb/s InP-based VCSEL modules were
manufactured and used in robust prototypes of the 1300 nm links realized in the project. VIS
also developed InAs-GaAs quantum dot (QD) based edge emitting lasers suitable for high
temperature operation (>160oC) and also produced 1300 nm QD VCSEL wafers. Due to
foundry issues QD VCSEL fabrication could not be completed in the timescale of the project
though the work continues and the results will be presented at the SPIE Photonics West
conference (February 2015).
Integrated Optical Transceivers
Conjunct designed a long wavelength midboard parallel optical transceiver operating at 25
Gb/s per channel, Although the transceiver could regrettably not be completed due to lack of
available VCSELs, they successfully developed a novel waveguide based low-loss optical
coupling interface for the transceiver.
Demonstration Platform
Finally Xyratex designed and assembled two complete demonstration platforms to showcase
and characterise the full technology eco-system developed by the SEPIANet consortium and
carried out a comprehensive test and measurement regime on the demonstration platforms,
whereby optical data was conveyed along the backplane embedded optical waveguides
through the pluggable connector technologies from various optical test sources.
These efforts have culminated in the first successful demonstration of fully integrated planar
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glass waveguide optical backplane and pluggable connector platforms driven by system
embedded and external 850 nm and 1310 nm optical transceiver technologies and validated
for both in-system and system-to-system optical connectivity.
Potential impact (including the socio-economic impact and the wider societal
implications of the project so far) and the main dissemination activities and
exploitation of results
The project has enabled the first ever demonstration of a completely new type of optical
backplane and supporting technology eco-system, which offers significant advantages over
the state of the art in optical PCBs in some application areas, and thus will have a major
impact on the rapidly emerging commercial field of system embedded photonics across the
entire ICT spectrum including access networks, data centres and HPCs. Indeed with the
current interest surrounding silicon photonics technologies (for instance by Intel through the
Facebook OpenCompute initiative) and its projected proliferation in data centre and other ICT
environments, this is the only embedded planar waveguide PCB technology that could
accommodate the high-speed longer wavelength optical data inherent to silicon photonics
and, in general, longer wavelength network fabrics.
Project public website and relevant contact details.
www.sepianet.eu
E-mail: richard_pitwon@xyratex.com
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