The University of Southampton

Fibre Bragg Gratings Group

Our PhD Projects:


Wavelength-flexible, single-frequency fibre lasers

Supervisory Team: Dr Morten Ibsen, Prof. Jayanta Sahu

Fibre lasers have seen a rapid development in output power and performance over the past three decades and have revolutionised the application space for photonics. Some applications specifically require high power to perform the intended tasks whilst others require low noise and narrow linewidth. Increasing the output power from fibre lasers has been the focus of intense research for decades for applications in scientific research, industrial processing and manufacturing, and defence and security, and has helped to develop a plethora of new fibre types and pump sources. However, one aspect of fibre lasers that has been lagging behind is the continued development of wavelength-flexible single-frequency sources to support and facilitate an increasing need and demand in parallel areas of practical applications incl., high-precision metrology, spectroscopy, remote sensing, frequency conversion, gravitational wave detection, coherent LIDAR, and for emerging quantum computing applications all of which require sources with very narrow linewidths at or below the kHz level. Lasers with narrow linewidths are also required in coherent combination of multiple fibre laser beams to enable very high power-levels (100s of kW CW), and so there is an urgent need to continue to innovate and develop a range of properties of fibre lasers in parallel, including those of wavelength-agile, narrow linewidth sources, which is the topic of this PhD project. 

Your role will initially focus on developing, demonstrating, and characterising the fibre laser sources and will subsequently aim to utilise the developed technology in a range of the application areas mentioned. It is largely an experimental project, but some theoretical modelling will also be required to guide the laser developments and help analyse the generated data and results. The project offers considerable opportunities for applicants who show strong innovation as well as a desire to broach new areas of science and technology. Previous experience with optical fibres and/or lasers is beneficial but not essential. 

  • Entry Requirements: A very good undergraduate degree (at least a UK 2:1 honours degree, or its international equivalent) in physics or a related discipline. 
  • Funding: For UK students, tuition fees and a stipend at the UKRI rate plus £2,000 ORC enhancement tax-free per annum for up to 3.5 years (totalling around £21,000 for 2024/25, rising annually). EU and Horizon Europe students are eligible for scholarships. CSC students are eligible for fee waivers. Funding for other international applicants is very limited and highly competitive. Overseas students who have secured or are seeking external funding are welcome to apply..
  • How to apply: Applications should be made online
  • Closing date: Applications are accepted throughout the year and several start dates throughout the year are possible. Applications for the typical Sept./Oct. start should be received no later than 31 August.


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