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UNLOC Newsletter

Welcome to the UNLOC newsletter for 2013/14. UNLOC - UNLocking the capacity of Optical Communications - is a Programme Grant funded by the Engineering and Physical Sciences Research Council to research the future of optical communication systems. It is a collaborative project between UCL and Aston University, in collaboration with many industrial partners.

Our research is focused on optical communication systems and networks that go beyond the limits of current technology, maximise channel capacity and are tailored to the nonlinear optical channel. Read more...

A new video clip takes you into the UNLOC labs to find out more about the aims of the project, and the team involved:

Keep up with ongoing project news on our recently-launched Twitter feed.

UNLOC Recruitment

We have been very fortunate to recruit outstanding individuals to work with us, and the UNLOC team is now complete. We are proud of the team of talented, dedicated researchers and students we have on board. A few of those who have joined us over the last year are...

Dr Alex Alvarado - UCL
Alex joined UNLOC in April 2014, having previously worked at the University of Cambridge as a Newton International and Marie Curie Fellow. He completed his PhD at Chalmers University of Technology, Sweden. His expertise and focus are on digital communications, coding, and information theory. His current work is focused on channel capacity aspects of nonlinear fibre channels.

Dr Yaroslav Prylepskiy - Aston
Yaroslav is working with UNLOC on the application of the Nonlinear Fourier Transform to long-haul transmission problems. He has previously worked as a Research Fellow at the BI Virkin Institute for Low Temperature Physics & Engineering, Kharkov, Ukraine, having completed his PhD there in 2003.
Dr Marc Stephens - Aston
Marc, an UNLOC Associate RA, is investigating both optical phase conjugation for nonlinear compensation and parametric optical amplification as a potential replacement for the EDFA. He has worked in the field of optical communications for ~15 years, including positions in optical comms. R&D at Nortel, Marconi and Ericsson.

Dr Tianhua Xu - UCL
Tianhua’s work is focussed on modelling fibre nonlinearity mitigation in the high spectral efficient WDM long-haul transmission system using advanced modulation formats. He received his PhD in Sweden, at KTH-ACREO, in the area of high speed optical fibre communications and digital signal processing in coherent detection.
Numeorous PhD Students are associated with UNLOC, including Gabriele Liga, Changle Wang, Daniel Elson and Nikita Shevchenko. See the UCL Optical Networks Group and Aston Institute of Photonic Technologies web pages for more information.

UNLOC Team Meets for Creative Problem Solving Workshop

The complete UNLOC team met together for the first time on 28-29 April, to take part in an EPSRC Creativity@Home workshop focussed on developing creative new project ideas. Facilitators from KnowInnovation worked with the team on a variety of exercises to enable them to think about their research in new ways: the team looked at the opportunities for UNLOC over the next three years of the project, as well as ahead to potential longer-term impacts. Read more...
The UNLOC team at the EPSRC Creativity@Home workshop

UNLOC External Advisory Board Meeting

The UNLOC External Advisory Board met for the second time on 20th May for an update on the progress of the project. The board is chaired by Dr Alastair Glass, chair of Tyndall National Institute, and is composed of leading national and international experts. It provides advice to the UNLOC team on three aspects of the project: quality of the research in the international context, industrial relevance, and impact and relationship to other leading UK and international programmes.

The meeting was held at Aston University, and included poster presentations from all PhD students and post-doctoral researchers, which the board noted as a particular highlight of the day. The board will meet next in the spring of 2015.

Publications to Date

This has been a very productive year with numerous publications. All publications to date are listed on the UNLOC website, including 61 peer-reviewed journal and conference papers and 24 invited talks.

Recent Research Highlights

New Digital Transmitter and Super-Receiver in Place

A new software-defined transmitter is now in place. The transmitter, set up in 2013, allows UNLOC researchers to generate high-order, advanced modulation formats, enabling more information to be transmitted, making more efficient use of the finite optical spectrum. After some fine-tuning, the transmitter has been working well with initial results of the work are due to be presented next week at ECOC 2014.

The transmitter enables digital spectral shaping, increasing spectral efficiency; and predistortion, allowing the mitigation of channel impairments. A frequency-locked comb source is used to reduce the channel spacing to the Nyquist rate, preventing cross-talk between channels.

During 2014, the acquisition of new Agilent 160 GS/s 63 GHz analogue electrical bandwidth real-time sampling oscilloscope system was completed.  Combined with high bandwidth (70GHz) balanced photodiodes this has given us an opportunity to implement a digital super-receiver for simultaneous coherent detection and digital signal processing of multiple optical channels.

Future work will focus on the exploration of optimised DSP and coding techniques to increase channel capacity over a variety of fibre types.

The first results of this work will be presented at ECOC 2014, in papers by Dr Robert Maher et al: “Linear and Nonlinear Impairment Mitigation in a Nyquist Spaced DP-16QAM WDM Transmission System with Full-Field DBP”. P.5.10, Lidia Galdino et al: "Unrepeatered Transmission over 253.4 km Ultra Low Loss Fibre Achieving 6.95 (b/s)/Hz SE using EDFA-only Pre-amplifier." P5.2, and Masaki Sato et al: "Frequency Diversity MIMO Detection for Dual-Carrier DP-16QAM Transmission." Th.2.5.1.

System and Network Test-beds

Both sites have extensive recirculating loop test-beds,  enabling flexible and systematic study of transmission in a range of scenarios and fibre types and distances ranging from several hundred km to trans-oceanic distances of >10,000km.  Both UCL and Aston Institute of Photonic Technologies (AIPT) have recently finished building shorter, landline-distance straight line optical transmission testbeds which emulate installed fibre optic infrastructure used by communications companies throughout the world, and can help investigate new and legacy network configurations.
The Aston system consists of the latest single mode fibre donated by Sterlite Technologies. The fibre is spliced into 15x100km spans (19 dB/span) amplified using state of the art dual-stage erbium doped fibre amplifiers (EDFAs). The amplifier design provides a maximum output power of +23dBm, variable gain from 15 to 32dB, mid stage loss of up to 10dB, and wide optical bandwidth allowing up to 96 channels to be simultaneously amplified. The design is equivalent to that used by leading optical communication companies such as Alcatel-Lucent or Ciena.

The system can be configured as either a modern coherent based system where dispersion compensation is performed electronically, or a more traditional optical communications system where dispersion compensation is performed periodically at each amplifier site. It consists of three 19inch racks which are moveable throughout the AIPT facility: each rack houses 500km of fibre and the associated optical amplifiers, thus offering a very flexible and reconfigurable testbed. The system will be used in forthcoming experiments investigating optical phase conjugation, and also to investigate next generation fibre optic parametric amplification.

The UCL system is 1200km, also with 100km spans (20 dB/span) and integrated with software-defined transceivers, donated by Ciena, and a 16x16 Polatis switch to investigate networking applications.

Exceptional UNLOC Research Highlighted by the American Physical Society


A recent paper by Aston researcher Yaroslav Prylepskiy has been featured on the APS Physics website.

APS Physics selects highlights from the Physical Review journals, showcasing the most important developments across the discipline. The paper, Nonlinear Inverse Synthesis and Eigenvalue Division Multiplexing in Optical Fiber Channels, introduces a new approach, the nonlinear inverse synthesis method, for digital signal processing, based on encoding the information directly onto the nonlinear signal spectrum. It was published on 1st July in Physical Review Letters, where it was picked as one of the editor's suggested papers. Read more...

Regeneration Limit of Classical Shannon Capacity

A theoretical framework has been developed for calculating the Shannon capacity for nonlinear noise squeezing channels. The gain in Shannon capacity due to noise squeezing was calculated analytically.
This research paves the way for designing communication channels with constructive nonlinearity and capacity exceeding capacity of linear channels.

The results have been published in Nature Communications: “Regeneration limit of classical Shannon capacity”. Sorokina MA, Turitsyn SK. Nature Communications 5, Article number: 3861 (2014) Read more...

Optical Phase Conjugator used to Demonstrate the Possibility of Transmission Beyond the Shannon Limit

UNLOC researchers have demonstrated, for the first time, that it is possible to transmit information beyond the nonlinear Shannon limit using optical phase conjugation, a simple nonlinear optical device, which can be thought of as a mirror for the spectrum. It was demonstrated that this spectral mirroring reverses at least 70% of the nonlinear signal distortion. Read more…

Awards for UNLOC Researchers

Prof Andrew Ellis (Aston) received the Royal Society Wolfson Research Merit Award. The award was made in recognition of Prof Ellis’ considerable contribution to optical communications research, and will enable him to develop collaborations and further the impact of his research.
Dr Domaniç Lavery (UCL) has been awarded the 2013 Marconi Society Paul Barran Young Scholar Award, which recognises academic achievement and leadership in the field of communications and information science. The award committee recognised Domaniç’s outstanding work in coherent passive optical networks (PONs) for access applications, his excellent academic record and evident dedication to the improvement of society through his work.
Prof Polina Bayvel (UCL) received the IEEE Photonics Society Engineering Achievement Award. This prestigious award, which recognises an exceptional engineering contribution having a significant impact on the development of laser or electro-optic technology, has been awarded to Prof Bayvel for "seminal advances in optical networks, including efficient wavelength routing architectures and electronic DSP algorithms to mitigate data degrading effects".

Other Awards and Prizes 2013 - 2014 (selected):

Prof Polina Bayvel: RS Clifford Paterson Lecture and Medal
Prof Andrew Ellis: EPSRC Established Career Fellowship
Dr Lidia Galdino: Ciência sem Fronteiras Fellowship renewal
Dr Domaniç Lavery: UCL Lombardi Thesis Prize
Dr Seb Savory: RAEng / The Leverhulme Trust Senior Research Fellowship
Prof Sergei Turitsyn: Rozhdestvensky Optical Society (Optical Society of Russia) AA Lebedev Medal

Recent Outreach and Advocacy

UNLOC featured at a recent schools' outreach event - the Big Bang Fair London. The event, held at Alexandra Palace on 8th July, showcased the science and engineering work taking place across the capital, with the aim of encouraging interest in STEM subjects among young people. Read more...

Prof Polina Bayvel participated in the launch of the Your Life UK government campaign. The campaign, launched in May 2014, aims to increase the number of students studying STEM subjects at A-Level by 50% over the next three years.

Prof Andrew Ellis gave a presentation at the Industry and Parliament Trust Breakfast on Wednesday 18th June - Tech, Media and Telecoms: Lessons from Across the Pond. He focussed on the impact of major investments in telecoms on economic growth and identified a gradual shift in the way in which the chasm between good research and commercial products has shifted. Read more...

UNLOC was represented at a recent KTN event - Photonics: Revolutionising our World.  Organised by the Knowledge Transfer Network (Electronics, Sensors, Photonics), together with UCL and NPL, the event was held at the Science Museum on 19th June. Read more...

Strong UNLOC Presence at Major Optical Communication Conferences

Optical Fiber Communication Conference 2014


UNLOC had a major presence at the Optical Fiber Communication Conference (OFC) 2014. Five UNLOC papers were presented at the conference, held in San Francisco from 9th - 13th March. UNLOC staff also participated in a rump session, "Will Traffic Growth Break the Internet - and Can Optical Communications Help?".  Read more...

UK Photonics Research Showcase - ECOC 2013

Co-sponsored by UNLOC, the UK Photonics Showcase took place at the European Conference on Optical Communication (ECOC) 2013, held in London in September 2013. The showcase celebrated the strength of UK photonics research, highlighting the major programmes – including UNLOC – playing a key role in current research.
Prof Polina Bayvel (pictured above at the event, with HyperHighway PI Prof Sir David Payne) introduced the project and spoke about the importance of ‘unlocking’ the capacity of existing fibre infrastructure, and maximising the capacity of any new fibres.

The UNLOC presence at ECOC continued with the presentation of five papers from staff and PhD students.
UNLOC papers have been presented at many other conferences over the past year, including the International Conference on Transparent Optical Networks (ICTON) and the OptoElectronics and Communication Conference (OECC). A complete list of UNLOC papers can be found on our website

Looking Ahead

ECOC 2014


Two UNLOC researchers - Deputy Director Prof Sergei Turitsyn and Senior Research Associate Dr Robert Maher - will give invited talks at ECOC 2014 in Cannes next week.  Prof Turitsyn will speak on "Capacity-achieving transmission techniques in nonlinear links", and Dr Maher on the "Fast Wavelength Switching Transceivers for Bandwidth on Demand Based Coherent Optical Networks".

Eight other UNLOC papers will be presented at the conference, listed here.

Royal Society Clifford Paterson Lecture

Polina Bayvel will present the 2014 Royal Society Clifford Paterson Lecture on 27th October 2014, speaking on the topic of “Communicating with Light”, and will describe the challenges and limits of communicating with light and the advances in optical and digital signal processing to maximise optical network capacity.  Prof Bayvel has been awarded the lecture for her fundamental research in high bandwidth digital communications and nonlinear optics.

The lecture will take place at the Royal Society, London, from 6:30-7:30pm, and is free and open to all. For more information see the Royal Society website.

Working with UNLOC

We are happy to host academic research visitors from industry and academia, and support applications for postdoctoral fellowships under a variety of schemes, including: Royal Society, Royal Academy of Engineering, EPSRC, Newton and Marie-Curie Fellowship schemes. If you are interested in exploring the possibilities, please get in touch at
If you would like more information about UNLOC, or wish to arrange a visit to our labs, please email us at
UNLOC is a collaborative project between UCL and Aston University. The project is funded by EPSRC and supported by many industrial partners.
Copyright © 2014 UNLOC, All rights reserved.

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