Acronym: ocean

PROJECT FINAL REPORT

Project acronym: OCEAN

Project title: OOFDM (Optical Orthogonal Frequency Division Multiplexing) for Cost Effective Access Networks

Project duration: 3 years 3 months from August 2011 to October 2014
Coordinator (organization): School of Electronic Engineering, Bangor University

Scientific representative of the coordinator (name and title): Professor Jianming Tang

E-mail: j.tang@bangor.ac.uk
Project website address: http://ocean.bangor.ac.uk

During the project lifetime, some project results were already being exploited by the industrial partners, and it is envisaged that 400Gb/s OOFDM transceivers may be made commercially available in the foreseeable future. Furthermore, highly successful OCEAN result dissemination activities have been undertaken, which include: a) 64 scientific papers have been published/presented in world-leading professional journals and major international communications conferences; b) a GB patent application has been filed; c) the OCEAN project story has been covered globally; d) various demonstrations in trade shows; and e) a large number of OCEAN demonstrations to young students and general public at Bangor. Finally, OCEAN results have also been proactively promoted to IEEE802.3bm 100GE/400GE standards via participating in and presenting relevant OCEAN results to the IEEE802.3bm 100GE and IEEE 802.3 400GE Fibre Optic Task Force groups.

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  Develop world-first, commercially exploitable, cost-effective, versatile, >20Gb/s OOFDM transceivers with per user link parameter awareness, real-time performance monitoring, adaptive performance optimization, as well as sufficient system management features;
  
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  Explore and experimentally demonstrate various OOFDM PON architectures;
  
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  Undertake comprehensive lab trials of the OCEAN-developed OOFDM transceivers in a carrier-like environment for successfully providing real-time services.
  

As a direct result of the propositions, evaluation and optimisation of a large number of innovative OOFDM techniques covering a wide diversity of the PON technique spectrum, all the aforementioned key objectives were achieved successfully. In addition, a number of additional achievements were also made in terms of:

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  Experimental demonstrations of 30Gb/s real-time end-to-end multi-band OOFDM transceivers,
  
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  Experimental confirmation of the feasibility of utilising conventional 10G-class optical components to support >100Gb/s/λ OOFDM transmissions over simple intensity-modulation and direct-detection (IMDD) single-mode fibre (SMF) Ethernet systems,
  
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  Advances in terms of signal modulation and transmission, DSP algorithms, transceiver designs, multiple PON access techniques and PON network architectures,
  
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  Successes in project exploitation, result dissemination and impact on industrial standard bodies.
  

a) world-first demonstrations of a number of real-time, end-to-end, adaptive OOFDM transceivers operating at signal bit rates of up to 30Gb/s by making use of commercially-available, low-cost optical/electrical components. The OOFDM transceivers offer unique features including, for example, on-line performance monitoring and optimisation, DSP-based effective compensation of both linear and nonlinear component/system/network impairments, as well as performance flexibility and adaptability to both channel spectral characteristics and data traffic conditions; and

b) experimental confirmation of the feasibility of utilising conventional 10G-class intensity modulators to achieve >100Gb/s/λ OOFDM transmissions for Ethernet systems. These results indicate that the development of cost-effective, high-speed, flexible and intelligent OOFDM transceivers is practically feasible for the realisation of software-defined networking-enabled elastic optical networks satisfying highly dynamic end-users’ traffic patterns.

Apart from the above-mentioned key S&T achievements, a number of novel cutting-edge OOFDM techniques have also been proposed, evaluated and optimised, which cover a wide diversity of the PON technique spectrum in terms of:

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  Advanced signal modulation/generation and detection: a) proposed and evaluated two new technical concepts namely OOFDM-carrierless amplitude and phase (CAP) (OOFDM-CAP) modulation and fast OFDM; b) demonstrated a broad range of low-cost OOFDM intensity modulators based on semiconductor optical amplifiers (SOAs), reflective SOAs (RSOAs), distributed feedback lasers (DFBs), vertical cavity surface emitting lasers (VCSELs), reflective electro-absorption modulators (REAMs), electro-absorption modulated lasers (EMLs), cascaded RSOAs and optical injection-locked VCSELs.
  
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  Optical signal transmission: a) adaptive subcarrier/sub-band bit/power loading-induced maximizations of system performances and WDM impairment compensation in IMDD SMF systems; b) optical filtering-enabled compensation of the intensity modulator nonlinear effects in IMDD SMF systems, c) optical signal central launch-induced multi-mode fibre (MMF) transmission distance extension of MMF transmission systems, and d) the effective utilisation of RSOA intensity-modulation-induced frequency chirp to improve the transmission performance.
  
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  DSP algorithms: a) proposed and demonstrated novel DSP-based signal synchronisation techniques; b) developed and evaluated stage-dependent minimum bit resolution maps of full-parallel pipelined fast Fourier transform (FFT) and inverse FFT (IFFT) architectures to considerably reduce the logic resource usage, c) developed and evaluated Volterra equalisation DSP algorithms, and d) developed and implemented OOFDM transceiver prototype interface and MAC layer protocols.
  
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  Novel OOFDM transceivers: a) proposed and experimentally demonstrated multi-band OOFDM transceivers, b) proposed and experimentally demonstrated digital orthogonal filter-enabled OOFDM transceivers with software reconfigurable channel multiplexing and demultiplexing.
  
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  Multiple access techniques. Proposed and evaluated a novel PON access technique known as digital filter multiple access (DFMA).
  
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  PON architectures: a) demonstrated real-time colourless OOFDM multiple access PONs and explored their upstream performance characteristics including capacity versus reach as well as power budgets, b) proposed and experimentally demonstrated dual-RSOA-based self-seeded OOFDM PONs, and experimentally investigated the impacts of intra-cavity chromatic dispersion on the upstream performances of such PON architectures, and c) investigated the DFMA PON upstream performance characteristics and subsequently identified optimum digital filter design guidelines.
  

The OCEAN project has produced 64 research papers published in world-leading professional journals, and major international communications conferences including 8 invited conference presentations and one OFC2013 tutorial, and one GB patent has also been filed. For publication details, please see the publication list in Section 2. A1 of the report.

Numerical simulation models including adaptive bit and power loading-enabled OOFDM transceivers and black-box directly modulated DFB/VCSEL lasers have set the path for their implementation in the commercially available VPI Photonics software platform.

Apart from having incorporated time interleaved 70GS/s digital-to-analogue converters (DACs) into HHI’s commercially available Arbitrary Waveform Generators, HHI is currently marketing their OCEAN-gained OFDM-PHY/OFDM-MAC expertise and also advertising their different IP cores. In addition, HHI’s expertise in OFDM-MAC/Ethernet has also enabled HHI to win a ~250k€ development contract from a company.
Finisar has already commercialized their low modulation bandwidth analogue intensity modulators and detectors, which have been further optimised for accommodating OOFDM signals during the OCEAN project time.
By making use of Fujitsu’s high-speed and high-performance DACs/ADCs developed during the OCEAN project time, and conventional 10G-class direct modulated intensity modulators, in OFC 2014, Fujitsu announced that adaptive OOFDM transceivers operating at 100Gb/s/λ and simultaneously four wavelengths in parallel may be made commercially available in the foreseeable future. 400GE Ethernet and intra-/inter data centre communications links are the main targeted market for such transceivers.
By fully making use of the developed OCEAN prototypes and OOFDM’s rich DSP features, TerOpta aims to explore the feasibility of commercializing the DSP-enabled intelligent OOFDM transceivers with software reconfigurable channel multiplexing and demultiplexing. To enable TerOpta to undertake the task, an Innovate UK funded project “TERPON” has been secured involving TerOpta and Bangor University.
A Bangor University spin-off company, SmarterLight Ltd, has been established to exploit Bangor’s expertise in DSP and the OOFDM patent portfolio to develop universal transceivers for future SDN based elastic PONs with significantly improved network resource utilisation efficiency.
Social Impacts

The OCEAN project story has achieved global coverage. The story first appeared on BBC Technology website and BBC Wales news page on 6 Nov.2012. http://www.bbc.co.uk/news/technology/ and http://www.bbc.co.uk/news/wales/. The story was soon getting amazing multilingual coverage and Dutch, German, French, Spanish and Portuguese versions appeared, and followed by people from Mumbai at the end of the day! By the end of November 2012, there were 54 pieces of OCEAN information appearing all over the world. See the detailed list in Section 2 A2.

Project website address: http://ocean.bangor.ac.uk