Photonic Phase Conjugation Systems (PHOS)

The remarkable success of the internet is unquestioned, touching all aspects of our daily lives and commerce. This success is fundamentally underpinned by the tremendous capacity of unseen underground and undersea optical fibre cables and the technologies associated with them. Indeed, the initial surge in web usage in the mid 1990s coincides with the commissioning of the first optically amplified transatlantic cable network, TAT12/13 that allowed ready access to information otherwise inaccessible. Similarly, the remarkable growth of social media is supported by the introduction of optical fibres into data centres, allowing their tremendous growth. Exponential growth has been a characteristic of data communications since their first introduction in the 1970's and has been fuelled by the gradual introduction of radical technologies, such as optical amplification, wavelength-division multiplexing and coherent modulation. All of these technologies are today routinely deployed and it is widely acknowledged that fibres are becoming full. The limit to fibre capacity has its origin in the fact that the intense signals are significantly distorted by nonlinearly (a similar effect to overdriving loudspeakers). This distortion limits the maximum amount of information which may be transmitted across and optical fibre link, and unless combated, the nonlinear response will result in a capacity crunch, limiting access to the internet to today's levels. Faced with the ongoing exponential growth in demand, unless these restrictions are lifted many parallel systems will be required, resulting in exponentially increasing energy consumption, until the cost of this resource becomes prohibitive and finally curtails growth.
Only one technology, optical phase conjugation (acting like a mirror for colours), has been shown to offer the prospect of supporting continued internet growth without the need for widespread use of multiple fibres and the associated growth in energy consumption. Very much like Newton's Prisms, optical phase conjugation allows the distortion of one fibre (analogous to spectral spreading in Newton's prisms) to be compensated by a second identical fibre.
In PHOS, we will
- Optimise the devices which perform this conjugation, both in terms of the assessment of fundamental nonlinear materials and in terms of optimised sub-system configuration.
- Demonstrate orders of magnitude increase in the capabilities of optical fibres for both practical point-to-point links with non-uniform span lengths and for optical networks with a plethora of diverse routes.
- Verify that the use of optical phase conjugation is cost effective, both in terms of reducing the cost of a network deployment compared to existing products and in terms of enhancing the service provided to customers through higher capacity with lower latency.
Furthermore, as optical phase conjugation will transform the capabilities of the network, PHOS will work to remove bottlenecks within the network transmitters and receivers, increasing their performance by an order of magnitude, resulting in 10 times faster connections. The approach of compensating impairments in the optical domain, combined with simplified digital signal processing and enhanced exploitation of fibre bandwidth will reduce the cost, size and power consumption associated with providing 10's of Tbit/s of capacity per optical fibre.
If successful, PHOS will enable massively increased data capacities from the employment of Optical Phase Conjugation, giving the UK the most advanced optical communication network and a strong position to become a leading supplier of the technology worldwide.

The primary societal impact of PHOS will be to facilitate the continuing growth of digital economy by significantly postponing the impending capacity crunch. The implications that this will bring to all aspects of modern society are remarkable. By working with UK Photonics Communications industry, solutions developed in PHOS will support the delivery of full-fibre access, which enables outstanding service delivery of, for example, low latency high definition video conferencing for domestic use and low latency transoceanic transmission for financial trading. By allowing for the development of a core network of sufficient capacity, PHOS will enable the increased effectiveness of initiatives, such as e-medicine and e-public services and will so contribute the evolution of quality of life. Similarly, by preventing an exponential growth in network energy consumption, PHOS will contribute to environmental sustainability.
Scientifically, PHOS proposes to combine the communications activities of two of the world's leading centres of excellence in photonics with the ambition of significantly enhancing their existing global influence through an increased scope of research and critical mass. Specifically PHOS will:

1. Maintain a high quality core science programme in collaboration with its partners within the network equipment and operator communities. Together the investigators have published over 700 peer reviewed conference and journal papers and both collaborate widely in Europe, partnering in more than 12 EU projects since 2006. In addition to UK collaborations, PHOS intends to continue to play a leading role in major European programmes with major companies such as Nokia, Coriant, Huawei, Telefonica, Finisar, OFS, Oclaro, Sterlite and Ciena.

2. Integrate fundamental and applied research within the programme to create industry-relevant technologies that will lead to commercial products. This will involve the generation of valuable IP (targeting 2 patent applications or one know how transfer, and one spin out company over the duration of the project) and regular communication with the UK photonics industry, ensuring the industrial relevance of the research and providing direct exploitation routes benefiting the UK economy. PHOS will also support the growth of existing SMEs by helping to develop innovative new products, enabling access to new sources of research funding, providing training and supporting the creation of new ventures.

3. Foster public awareness through education and outreach programmes, encouraging all PhD students to participate in Aston University's outreach program and the ORC's Lightwave Roadshow. The applicants will participate personally in appropriate events with a wider public audience. Press-releases to non-specialist journals and professional magazines will also be used to publicize breakthroughs of particular importance to the wider public.

4. We anticipate that a successful execution of this proposal will lead to significant international interest in associated technologies. We will welcome the participation of other international research groups in advancing the knowledge base and increasing the likelihood of adoption of our own work and will organise an international workshop to facilitate direct scientific exchange and future collaborations.

5. Support the development of a highly skilled economy by training and fostering the development of a number of early-career researchers and students.

Thus the overall program of research enabled by this project is expected to have wide ranging benefits to the scientific community (development of a new approach to communication system design), the communications industry (simultaneous increase in available capacity and reduction in energy consumption) and wider society (continued growth of digital communications).