Optical Fibre Communications

Developments in fibre technology have revolutionised society, allowing first low-cost, high-quality voice communications, and more recently the development of the internet. 

The group has been at the forefront of optical fibre communications since the very earliest days of the field providing several critical contributions including the invention of the erbium doped fibre amplifier Ė a device that eliminated fibre loss as the fundamental limiting factor to signal transmission and which is installed in all modern optical communication networks.

Despite the downturn in communications that occurred earlier this decade, optical communications remains by far the largest market for photonics and as such it represents one of the ORCís primary research areas. 

Current topics of major interest include the use of optical signal processing to increase the speed and efficiency of optical networks, lasers and amplifiers for next generation telecommunication systems, and the development of ultrahigh bit rate data transmission technology. 

Group webpage

PhD Projects:

Intra- and inter-band nonlinear applications of silicon
photonic waveguides

Supervisor: Prof P Petropoulos

The exciting prospect of compact highly nonlinear waveguides operating over broad wavelength ranges is likely to impact a multitude of application areas, spanning from communications to absorption spectroscopy, chemical and biological sensing and LIDAR applications. We have recently studied the nonlinear properties of silicon germanium alloys and shown that they are a suitable candidate for applications involving the translation of optical signals across largely spaced wavelength bands.

This is a project for a student interested in exploring applications of nonlinear silicon germanium waveguides through the design of application-specific devices. The project will also involve a comparative experimental assessment of waveguides fabricated in additional material platforms, including silicon nitride and amorphous silicon. Applications of interest include phase-sensitive amplification, the nonlinear generation of broadband frequency combs and supercontinuum generation. Wherever relevant, the applications will be tested using the ORCís extensive telecommunications systems infrastructure, which include ultrafast optical and electronic diagnostic tools for advanced modulation formats, as well as immediate access to the UKís National Dark Fibre Infrastructure for experimentation on optical transmission.


Novel transmission and processing schemes for ultra-high
speed telecommunication signals

Supervisor: Prof P Petropoulos
Co supervisors: Prof D J Richardson, Dr F Parmigiani

The optical fibre communications industry faces some significant challenges in recent years. As transmission rates in optical networks constantly increase, and with the concerns over the energy consumption of communication networks becoming ever more relevant, there is a compelling argument for adopting new techniques for the implementation of signal processing of communication signals. On the other hand, the rise in demand for internet traffic is such that necessitates the adoption of new transmission techniques in order to ensure that the available bandwidth is sufficient.

A range of projects in the Optical Fibre Communications Laboratory investigate technologies that address these challenges. The student working in this area will have the opportunity to work with new fibre types, combine them with state-of-the-art devices and identify their potential for applications. Topics of interest include the generation and manipulation of new frequencies, novel modulation formats, new transmission techniques and spatial-division multiplexing, format conversion, analogue-to-digital conversion and signal regeneration.

The project benefits from established collaborations with other UK and European institutions. It makes use of the strong facilities of the telecommunication systems laboratory of the ORC. These include full electronic testing capabilities up to 56 Gbit/s, optical diagnostic tools with a bandwidth in excess of 500 GHz and a unique installed fibre transmission line originating from the lab, and linking the ORC to other collaborating laboratories across the UK


All-optical signal processes enhanced by multi-mode nonlinearities

Supervisor: Dr F Parmigiani
Co-supervisor: Prof D J Richardson, Prof P Petropoulos

Optical communication networks are undergoing a major transformation: it is widely recognised that there is a need to accommodate multi-terabit per second communication traffic, using fast and low-latency solutions with even more individual wavelength carriers, all the while improving energy efficiency. These requirements call for novel optical amplifiers exhibiting substantially larger bandwidth (and thus also data capacity) than the widely-adopted erbium doped fibre amplifier (EDFA) with fixed (35 nm) bandwidth. 3rd-order nonlinear parametric processes are very interesting alternative solutions to extend the amplification bandwidth by a factor in excess of ten.

The student working in this area will explore all-optical signal processing applications based on 3rd-order parametric effects in multi- (or few-) mode media. This extra spatial dimension will be used to enhance the performance of a variety of applications, spanning from broadband parametric amplification to the generation of wavelength-tunable sources at potentially any desired wavelength.

The student will have the opportunity to work with new fibre types or materials and combine them with state-of-the-art electronic capabilities in strong collaboration with the fibre fabrication and the computational groups within the ORC.


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