The University of Southampton

Coherent Optical Signals

This group is led by Professor Radan Slavík and it is part of the Advanced Fibre Technologies & Applications Group led by Prof David J Richardson.

The generation, manipulation, and detection of optical signals carrying information by signal phase (or amplitude + phase) lies at the core of our research.

In recent years, there have been significant developments in lightwave technologies enabling wide exploitation of optical phase, as exemplified in particular by the dawn of Coherent Optical Communications - the key enabler for the growth in the capacity of the Internet. This is due to many key breakthroughs in laser technology (low-noise low-cost and compact lasers), new revolutionary concepts that have recently  been introduced (e.g., the Optical Frequency Comb, the significance of which was demonstrated by the award of a Nobel Prize in 2005), and significant advances in electronics that, thanks to the increased speeds now possible, can accommodate the processing of very complicated coherent (amplitude + phase) signals.

Our main areas of interest are:

1) Sources and local oscillators for the generation and detection of advanced coherent communication signals, including multi-carrier formats.Future Optical Communications modulation formats have strict requirements in terms of laser linewidth (transmitter and local oscillator for demodulation) and optical signal to noise ratio (OSNR). Additional requirements on absolute frequency stability may be imposed by multi-carrier (superchannel) systems. We investigate how modern tools (e.g., Optical comb techniques in conjunction with injection locking) may address these needs.

2) Photonics-aided coherent generation and multiplexing/demultiplexing of advanced modulation format signals.
Electrical multiplexing of data up to very high capacities (e.g., 1 Tbit/s per channel) is likely to be tricky and OSNR limited.  We investigate alternative possibilities of multiplexing/synthesizing the key IQ-modulation formats directly in the optical domain, preferably by direct modulation of semiconductor optoelectronics devices (e.g. through the injection of carriers generated via comb technologies). The same applies for the signal de-multiplexing.

3) Precise time/frequency processing and  transfer over fibre networks
We develop techniques to improve the transfer of precise time and frequency over optical fibres. Our work  includes research into novel optical components and methods of processing/characterizing ultra-precise optical signals.

The key to our work is collaboration with industry who actively support several of our PhD students. We closely collaborate with:

  •   Eblana Photonics, Ireland
  •   Oclaro, UK
  •   Phoenix Photonics, UK
  •   National Physics Laboratory London, UK

PhD opportunities
We are currently seeking PhD students for experimental works in the area of optical communications, metrology, and optical signal processing.

Find out about our PhD projects.

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