HERMES is aimed at realising a Ge and GeSi material platform that will be aimed primarily at sustaining optical interconnect circuits to meet the density, data rate and power consumption requirements for the continuation of Moore's law beyond 2020. The ITRS roadmap shows a saturation of the number of electrical pins required for input/output on microprocessors beyond 2020 to about 3000 with current technology. This saturation with an ever increasing latency and a limited on-chip clock speed is a bottle neck that high density optical interconnects have to alleviate. To meet the ITRS 2020 goals the target is clear, with over 100 Tb/s off chip IO capability and power consumption for an entire optical link on the order of 100fJ/bit. This work proposes a solution to this problem and provides a novel means of fabrication to go beyond the capabilities of standard planar silicon photonics circuits. To do so we aim to develop a multilayer optical platform based on localised Germanium/Silicon compounds on insulator compatible with the fabrication of micrometre sized cavity based structures enabling devices such as modulators and detectors. The growth of laser sources based on III/V materials or doped Germanium could also be envisioned but this is beyond the scope of this proposal. The proposed platform will establish a means to fabricate and demonstrate micrometre scale optical devices fit to tackle the 3 dimensional, high density, low voltage and low capacitance requirements needed for very large scale optical integration necessary for optical on chip interconnects.

Silicon photonics promises to revolutionize modern optoelectronics by allowing for dense integration of components that feature the best optical and electronic functions of the material. In recent years great progress has been made in this area, with many silicon photonic devices now meeting (or exceeding) the performance requirements of state-of-the-art systems. This includes ultra-low loss interconnects as well as high speed optical regenerators, amplifiers, modulators, and detectors, which form the building blocks for photonic circuits. However, to date, much of this progress has been achieved on silicon-on-insulator (SOI) platforms with a thick buried oxide layer, which are largely incompatible with electronic device development, and relatively expensive, thus precluding truly integrated systems from reaching the high-volume market. Consequently, there are still crucial challenges to overcome before the performance benefits of SOI photonics outweigh the costs and design constraints, leaving the door open for alternative platforms to be considered. In this programme we propose to develop a low cost and low temperature laser materials processing procedure to fabricate high quality polycrystalline semiconductor photonic platforms that will rival the performance of their SOI counterparts. Laser processed polycrystalline materials are already well-established for use in electronic technologies where some performance can be sacrificed in favour of reduced processing costs, for example, in the backplanes of smart phones and televisions. However, if the polycrystalline grains can be grown as large as the individual components, then the optical (and electronic) properties will approach those of the single crystal materials. By building on the platform established by the electronics community, this work seeks to grow large grain polycrystalline materials to realize low loss photonic components. Importantly, the high localization of this laser crystallization procedure directly alleviates issues associated with multi-material and multi-layer photonic device integration, and can also be used to modify or repair the individual components at a late stage in the fabrication, helping to increase the production yield and reduce the costs of integrated systems. Furthermore, this method offers the unique advantage of removing the substrate dependence from semiconductor photonics, thus offering the possibility to extend the application space through the use of substrate materials with enhanced optical functionality, increased transparencies, or even flexible plastics. By reducing costs and barriers associated with device fabrication, our innovative project will set the scene for wide spread use of laser-engineered semiconductor photonic components in mainstream optoelectronic systems.

Silicon photonics is one of the largest and fastest growing areas of research and development of our time. The ability to exploit the semiconductor functionality to process and transmit data in the form of light offers a route to dramatically increase the speeds, capacities, and efficiencies of next generation optoelectronic systems. An important subset of this work is nonlinear silicon photonics, where the aim is to make use of the large, ultrafast, nonlinearity of the material to intricately control and manipulate these light-based signals using light itself. Nonlinear processes in silicon have been widely studied, with significant device demonstrators including Raman lasers, parametric amplifiers, and high-speed modulators. However, most of these devices have been constructed from single crystal material platforms that are notoriously difficult to integrate, either with other elements on-chip or with the optical fibres that are used to link the systems together. Thus, if nonlinear silicon devices are to make the critical transition from a research curiosity to commercially viable products, these integration hurdles must be overcome. The work in this fellowship application will develop procedures to directly incorporate nonlinear optical components fabricated from cheap and easy to deposit materials within highly functional photonic systems. Compared to their single crystal counterparts, these materials offer a number of key advantages as they are compatible with a wide range of substrates, can be shaped in three dimensions, and can even be post-processed to fine-tune the optical properties and/or the waveguide structure. The components will be fabricated in both fibre and planar form, thus opening an innovative route towards linking these two platforms - one of the most important design challenges in the field of silicon photonics. Following optimization of the integration methods and materials, a range of nonlinear optical systems will be constructed, with the goal to obtaining systems that are smaller, faster, and more efficient. Although the primary focus of this project is the development of integrated platforms for optical communication systems, by extending the device operation into the mid-infrared wavelength region there will be scope to target applications in important areas such as environmental sensing, healthcare, and public security. By looking beyond the traditional single crystal chip-based components to consider more flexible materials and geometries, the work in this programme will help bring the vision of truly integrated nonlinear silicon platforms to fruition.

We propose a Centre for Doctoral Training in New and Sustainable PV. It will support the transformation of PV in the UK will that will in turn aid the country to achieve its renewal energy obligations, and will generate jobs in the technology sectors as well as local manufacturing and installation. The CDT allows for the distributed nature of PV research in the UK with a multi-centre team of seven partners covering all aspects of PV research from novel materials through new device architectures to PV systems and performance. The PhD projects and training span engineering and physical science expertise in materials and device physics, electronic engineering, physical and synthetic chemistry, operations management and manufacturing. The CDT graduates will be capable of transforming state of the art R&D across the PV technologies and, in so doing, contribute to the production and implementation of improved PV products and systems. All partners are members of the SuperSolar Hub and hence already coordinate integrated PV research and training. Students in the CDT will join a thriving research community. The team has unrivalled access to shared facilities in the best state of the art laboratories in the UK. Our group approach brings together expertise with a breadth and depth for training and research that could not be assembled in any other way. Moreover, the collaboration allows us to cut across the traditional boundaries in PV and enables exciting research vectors to be followed in New and Sustainable PV CDT agenda. International collaborations and formal exchange agreements will emphasise the global aspects of advanced research that are important for the development of a leadership group. The CDT members will interact with related research themes such as photochemical conversion of fuels for energy and other applications, and heating and cooling by solar radiation and will be a proactive member of the UK wide Network of Energy CDTs. Our goal is to train the best researchers with a flexible mindset able to communicate across different disciplines and be leaders in the emerging PV industry for advanced technologies. We will provide the training required for graduates to join the sustainable energy and PV sectors. We will establish a real identity of purpose and commonality in each cohort through a training programme designed to give students an understanding of all aspects of PV, including implications for society and an experience of a commercial environment. Students will be provided with a bespoke curriculum and training programme that exposes them to: (i) underpinning fundamentals across all the relevant disciplines, (ii) current state-of-the-art in knowledge and challenges in scale-up and systems, and (iii) unparalleled opportunities to engage in leading-edge interdisciplinary research projects as part of a national team. We will create a doctoral training environment in which students benefit from leading academic expertise and world-class facilities to develop their knowledge as well as the tools to innovate and create within their selected research theme. The unique cross functional skill-sets that our graduates will have will make them highly valuable to the academic community seeking to address ambitious basic manufacturing research challenges, and to industry, who have an urgent need for appropriately trained scientists and engineers able to support PV technologies within their commercial operations. To allow the students the chance to develop a common sense of purpose, each cohort will attend training events together. Courses will cover fundamental aspects common to all PV technologies and also advanced courses based on the partners' research expertise. There will be industrial and international placements. Coherence across the CDT will be aided by a virtual collaboration medium containing webinars and video lectures and pages where students and staff can collaborate via groups, and online forums.

We propose a Centre for Doctoral Training in New and Sustainable PV. It will support the transformation of PV in the UK will that will in turn aid the country to achieve its renewal energy obligations, and will generate jobs in the technology sectors as well as local manufacturing and installation. The CDT allows for the distributed nature of PV research in the UK with a multi-centre team of seven partners covering all aspects of PV research from novel materials through new device architectures to PV systems and performance. The PhD projects and training span engineering and physical science expertise in materials and device physics, electronic engineering, physical and synthetic chemistry, operations management and manufacturing. The CDT graduates will be capable of transforming state of the art R&D across the PV technologies and, in so doing, contribute to the production and implementation of improved PV products and systems. All partners are members of the SuperSolar Hub and hence already coordinate integrated PV research and training. Students in the CDT will join a thriving research community. The team has unrivalled access to shared facilities in the best state of the art laboratories in the UK. Our group approach brings together expertise with a breadth and depth for training and research that could not be assembled in any other way. Moreover, the collaboration allows us to cut across the traditional boundaries in PV and enables exciting research vectors to be followed in New and Sustainable PV CDT agenda. International collaborations and formal exchange agreements will emphasise the global aspects of advanced research that are important for the development of a leadership group. The CDT members will interact with related research themes such as photochemical conversion of fuels for energy and other applications, and heating and cooling by solar radiation and will be a proactive member of the UK wide Network of Energy CDTs. Our goal is to train the best researchers with a flexible mindset able to communicate across different disciplines and be leaders in the emerging PV industry for advanced technologies. We will provide the training required for graduates to join the sustainable energy and PV sectors. We will establish a real identity of purpose and commonality in each cohort through a training programme designed to give students an understanding of all aspects of PV, including implications for society and an experience of a commercial environment. Students will be provided with a bespoke curriculum and training programme that exposes them to: (i) underpinning fundamentals across all the relevant disciplines, (ii) current state-of-the-art in knowledge and challenges in scale-up and systems, and (iii) unparalleled opportunities to engage in leading-edge interdisciplinary research projects as part of a national team. We will create a doctoral training environment in which students benefit from leading academic expertise and world-class facilities to develop their knowledge as well as the tools to innovate and create within their selected research theme. The unique cross functional skill-sets that our graduates will have will make them highly valuable to the academic community seeking to address ambitious basic manufacturing research challenges, and to industry, who have an urgent need for appropriately trained scientists and engineers able to support PV technologies within their commercial operations. To allow the students the chance to develop a common sense of purpose, each cohort will attend training events together. Courses will cover fundamental aspects common to all PV technologies and also advanced courses based on the partners' research expertise. There will be industrial and international placements. Coherence across the CDT will be aided by a virtual collaboration medium containing webinars and video lectures and pages where students and staff can collaborate via groups, and online forums.