SwiTching And tRansmission (STAR)

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

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Description The project seeks to optimise architectures for optical transmission, enabled by the advent of high speed, high energy efficiency integrated optical switches.
Previous research has shown that it is possible to develop integrated optical switches with nanosecond switching times, which can route optical data at rates in excess of 10 Gb/s from as many as 16 input ports to 16 output ports. These switches can be compact, with dimensions less than 10mm and can exhibit energy efficiencies of 26pJ/bit.
This project however seeks to improve the performance of such integrated optical switches, both by improving the switching performance, yielding larger switches and by improving the energy efficiency of such switches.
A key development within the first 18 months of the project is the introduction of a new architecture within the optical switch fabric itself. This uses the very low penalty switching performance of Mach-Zehnder interferometers to develop compact switching elements with exceedingly low power consumption. These switching elements however suffer from poor crosstalk performance and whilst having lower losses than other switching architectures do exhibit a small optical loss. Both of these limitations can be overcome by following the switching elements with small semiconductor optical amplifiers and using a dilated architecture, which not only improve the crosstalk, but also compensate for any optical loss within the switch.
This development has enabled the fabrication of small 2x2 port optical switches, which can be used experimentally as building blocks to emulate larger switches. Such experiments have shown that integrated switch fabrics as large as 128x128 ports are feasible using this design.
Not only can larger switches be built, but their improved optical performance means that multiple wavelengths can be sent through each switching element simultaneously, enabling much higher data capacities to be realized.
These improvements indicate that the energy efficiency of such a switch is better than 1pJ/bit, two orders of magnitude improvement on our original optical switch fabrics.
Larger port count switches are currently being fabricated, with a 4x4 port switch expected soon, and designs for an 8x8 port switch complete.
Exploitation Route This project is contributing to the Greentouch consortium, whose aim is to 'to deliver the architecture, specifications and roadmap to increase network energy efficiency by a factor of 1000 compared to 2010 levels'. There are a number of key industrial collaborators within consortium, in particular Alcatel Lucent are very keen to perform laboratory demonstrations of the switching technology, as it appears to be a potential component in future high capacity internet routers.
Other industrial users have contacted us, expressing interest in using such a switch within telecommunications products.
Sectors Digital/Communication/Information Technologies (including Software)

Electronics
 
Description Global ICT energy consumption is rising significantly - unless disruptive technologies are developed it is predicted that it will consume in excess of 20% of global power consumption. Internet switches and routers consume large amounts of power, as their switching takes place in the electrical domain. It is possible to reduce this power consumption significantly if energy efficient high speed optical switch fabrics can be developed and be used as substitutes electronic packet switches currently used in the telecommunications networks. There are some significant barriers to this, given that telecoms operators would need to change how data is routed around the internet (essentially changing how the IP protocol works) but if this is done, then the opportunity for energy savings is a big one. Work within the project is developing initial integrated optical switch designs with an aim to improve their energy efficiency by several orders of magnitude. This will thus make a significant contribution to the reduction in energy consumption within telecommunications systems and cloud storage systems. The work on the switches has gone well and continues to receive a lot of interest from academia and industry as over time the amount of data delivered and processed by the global internet has grown exponentially. Integrated components have been realised with 16x16 port counts and we have shown that the technology can scale to the order of 1000x1000, which is sufficient for data centre deployment to connect racks of switches, replacing the majority of the data centre switch multiplex. This work is attracting significant interest from industrial partners such as Alcatel Lucent and was part of the industry inititiave to "green" the internet - Greentouch. Subsequently funding has been received from Microsoft Research who are working on an optical switch project for cloud based data centres and on disaggregating memory and processing in high performance computing. The integrated switch work is continuing with a move into developing heterogenous integration of Si and III-V photonics to allow much large switch sizes to be realised on a more compact platform, thus greatly improving integrated chip density.
First Year Of Impact 2014
Sector Digital/Communication/Information Technologies (including Software),Electronics,Environment
Impact Types Societal

Economic
 
Description EU H2020 - PICS4ALL project
Amount € 2,000,000 (EUR)
Funding ID 687777 
Organisation European Union 
Sector Public
Country European Union (EU)
Start 01/2016 
End 12/2018
 
Description Industrial contract
Amount £10,000 (GBP)
Organisation Microsoft Research 
Sector Private
Country Global
Start 03/2017 
End 07/2017
 
Description Large Scale Hybrid III-V and Silicon Optical Switch
Amount £613,833 (GBP)
Funding ID NMZE/251 
Organisation Zhejiang University 
Sector Academic/University
Country China
Start 11/2020 
End 10/2023
 
Description Research stduentship funding
Amount £100,000 (GBP)
Organisation Microsoft Research 
Sector Private
Country Global
Start 01/2019 
End 12/2021
 
Title Data relating to Scalable, Low-Power-Penalty Nanosecond Reconfigurable Hybrid Optical Switches for Data Centre Networks 
Description Data relating to Scalable, Low-Power-Penalty Nanosecond Reconfigurable Hybrid Optical Switches for Data Centre Networks 
Type Of Material Database/Collection of data 
Provided To Others? Yes  
 
Title Research data supporing "Hybrid MZI-SOA InGaAs/InP Photonic Integrated Switches" 
Description Experimental data in Microsoft Excel 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes