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 research is focused on one of our society's greatest technical challenges and economic drivers with impact on knowledge, economy, society and people as well as business and government activities. It aims to transform the development of the information and communication infrastructure. A high-capacity, flexible, cost-effective and efficient telecommunications and data infrastructure is of great national and international importance. The ability to communicate seamlessly, without delay, requires intelligent communications networks with high capacity, available when and where it is needed. To achieve this requires research advances in ultrawideband wireless and optical networks, as well as intelligent transceivers, new ultrawideband optical devices and algorithms. This is a fast-moving and internationally fiercely competitive field and to maintain international leadership requires the capability of not only making theoretical advances, but the also the ability of demonstrating these experimentally. Our vision is to create an advanced, world leading signal generation and detection test-bed for advanced communications systems research. The key feature of the proposed system are the ultra-low noise, high-resolution capture and analysis of complex broadband signals, more than quadrupling the achievable network capacity. This unique facility will allow the investigation of optical and wireless networks over a wide range of time- and length scales, including long-haul networks, data centres and enable the research into the ultra-wideband signal manipulation for the next-generation optical & wireless access networks. It will enable UCL and UK to consolidate and enhance its internationally leading position in communications systems research supporting a wide range of other areas.

Over the last decade, much interest of scientists and engineers working in optics and photonics has been attracted to the research and development of miniature devices based on the phenomenon of slow light. The idea of slow light consists in reducing its average speed of propagation by forcing light to oscillate and circulate in specially engineered microscopic photonic structures (e.g., photonic crystals and coupled ring resonators). Researchers anticipated that slow light devices will have revolutionary applications in communications, optical and radio signal processing, quantum computing, sensing, and fundamental science. For this reason, the research on slow light has been conducted in many academic laboratories and industrial research centres including telecommunications giants IBM, Intel, and NTT. However, in spite of significant progress, it had been determined that current photonic fabrication technologies are unable to produce practical slow light devices due to the major barriers: the insufficient fabrication precision and substantial attenuation of light. To overcome these barriers, this project will develop a new photonic technology, Surface Nanoscale Axial Photonics (SNAP) which will allow us to demonstrate miniature photonics devices with unprecedentedly high precision and low loss. SNAP is a new microphotonics fabrication platform invented by the PI of this project. In contrast to previously considered slow light structures based on circulation of light in coupled ring resonators and oscillations photonic crystals, the SNAP platform employs whispering gallery modes of light in an optical fibre, which circulate near the fibre surface and slowly propagate along its axis. The speed of axial propagation of these modes is so slow that it can be fully controlled by dramatically small nanoscale variations of the fibre radius. This project will develop the advanced SNAP technology for fabrication of ultraprecise, ultralow loss, tuneable, switchable and fully reconfigurable miniature slow light devices establishing the groundwork for their revolutionary applications in future Information and Communication Technologies. The success of the project will place the UK in the centre of this revolutionary development.

Dramatic progress has been made in the past few years in the field of photonic technologies, to complement those in electronic technologies which have enabled the vast advances in information processing capability. A plethora of new screen and projection display technologies have been developed, bringing higher resolution, lower power operation and enabling new ways of machine interaction. Advances in biophotonics have led to a large range of low cost products for personal healthcare. Advances in low cost communication technologies to rates now in excess of 10 Gb/s have caused transceiver unit price cost reductions from >$10,000 to less than $100 in a few years, and, in the last two years, large volume use of parallel photonics in computing has come about. Advances in polymers have made possible the formation of not just links but complete optical subsystems fully integrated within circuit boards, so that users can expect to commoditise bespoke photonics technology themselves without having to resort to specialist companies. These advances have set the scene for a major change in commercialisation activity where photonics and electronics will converge in a wide range of systems. Importantly, photonics will become a fundamental underpinning technology for a much greater range of users outside its conventional arena, who will in turn require those skilled in photonics to have a much greater degree of interdisciplinary training. In short, there is a need to educate and train researchers who have skills balanced across the fields of electronic and photonic hardware and software. The applicants are unaware of such capability currently.This Doctoral Training Centre (DTC) proposal therefore seeks to meet this important need, building upon the uniqueness of the Cambridge and UCL research activities that are already focussing on new types of displays based on polymer and holographic projection technology, the application of photonic communications to computing, personal information systems and indeed consumer products (via board-to-board, chip to chip and later on-chip interconnects), the increased use of photonics in industrial processing and manufacture, techniques for the low-cost roll-out of optical fibre to replace the copper network, the substitution of many conventional lighting products with photonic light sources and extensive application of photonics in medical diagnostics and personalised medicine. Many of these activities will increasingly rely on more advanced systems integration, and so the proposed DTC includes experts in computer systems and software. By drawing these complementary activities together, it is proposed to develop an advanced training programme to equip the next generation of very high calibre doctoral students with the required expertise, commercial and business skills and thus provide innovation opportunities for new systems in the future. It should be stressed that the DTC will provide a wide range of methods for learning for students, well beyond that conventionally available, so that they can gain the required skills. In addition to lectures and seminars, for example, there will be bespoke experimental coursework activities, reading clubs, roadmapping activities, secondments to collaborators and business planning courses.Photonics is likely to become much more embedded in other key sectors of the economy, so that the beneficiaries of the DTC are expected to include industries involved in printing, consumer electronics, computing, defence, energy, engineering, security, medicine and indeed systems companies providing information systems for example for financial, retail and medical industries. Such industries will be at the heart of the digital economy, energy, healthcare and nanotechnology fields. As a result, a key feature of the DTC will be a developed awareness in its cohorts of the breadth of opportunity available and a confidence that they can make impact therein.

This proposal seeks funding to create a Centre for Doctoral Training (CDT) in Connected Electronic and Photonic Systems (CEPS). Photonics has moved from a niche industry to being embedded in the majority of deployed systems, ranging from sensing, biophotonics and advanced manufacturing, through communications from the chip-to-chip to transcontinental scale, to display technologies, bringing higher resolution, lower power operation and enabling new ways of human-machine interaction. These advances have set the scene for a major change in commercialisation activity where electronics photonics and wireless converge in a wide range of information, sensing, communications, manufacturing and personal healthcare systems. Currently manufactured systems are realised by combining separately developed photonics, electronic and wireless components. This approach is labour intensive and requires many electrical interconnects as well as optical alignment on the micron scale. Devices are optimised separately and then brought together to meet systems specifications. Such an approach, although it has delivered remarkable results, not least the communications systems upon which the internet depends, limits the benefits that could come from systems-led design and the development of technologies for seamless integration of electronic photonics and wireless systems. To realise such connected systems requires researchers who have not only deep understanding of their specialist area, but also an excellent understanding across the fields of electronic photonics and wireless hardware and software. This proposal seeks to meet this important need, building upon the uniqueness and extent of the UCL and Cambridge research, where research activities are already focussing on higher levels of electronic, photonic and wireless integration; the convergence of wireless and optical communication systems; combined quantum and classical communication systems; the application of THz and optical low-latency connections in data centres; techniques for the low-cost roll-out of optical fibre to replace the copper network; the substitution of many conventional lighting products with photonic light sources and extensive application of photonics in medical diagnostics and personalised medicine. Many of these activities will increasingly rely on more advanced systems integration, and so the proposed CDT includes experts in electronic circuits, wireless systems and software. By drawing these complementary activities together, and building upon initial work towards this goal carried out within our previously funded CDT in Integrated Photonic and Electronic Systems, it is proposed to develop an advanced training programme to equip the next generation of very high calibre doctoral students with the required technical expertise, responsible innovation (RI), commercial and business skills to enable the £90 billion annual turnover UK electronics and photonics industry to create the closely integrated systems of the future. The CEPS CDT will provide a wide range of methods for learning for research students, well beyond that conventionally available, so that they can gain the required skills. In addition to conventional lectures and seminars, for example, there will be bespoke experimental coursework activities, reading clubs, roadmapping activities, responsible innovation (RI) studies, secondments to companies and other research laboratories and business planning courses. Connecting electronic and photonic systems is likely to expand the range of applications into which these technologies are deployed in other key sectors of the economy, such as industrial manufacturing, consumer electronics, data processing, defence, energy, engineering, security and medicine. As a result, a key feature of the CDT will be a developed awareness in its student cohorts of the breadth of opportunity available and the confidence that they can make strong impact thereon.