Biophotonics '17: Lecture by Prof. J. Roy Taylor

Fibre Based Supercontinuum Sources and Lasers

Prof. J. Roy Taylor

Professor J. Roy Taylor

Femtosecond Optics Group
Physics Department
Imperial College
Prince Consort Road
London SW7 2BW
United Kingdom

Tel: +44 207 594 7786
Fax: +44 207 594 7781
E-mail: jr.taylor@ic.ac.uk

Abstract

For applications in biophotonics, laser based sources with extreme versatility in wavelength coverage, pulse duration and pulse repetition rate are esential components. In the spectral domain, the fibre based supercontinuum source has had an enormous impact on such applications. The first supercontinuum source utilizing bulk optical components was reported around 1970 and by the end of the 1980s all the non linear processes that contribute to supercontinuum generation in optical fibre were identified and characterized, however, it was not until the application of photonic crystal fibre, albeit with a bulk fibre laser, in 1999 that supercontinuum sources were seriously considered as potential commercial devices for both the research laboratory and routine clinical operation. This later development was also linked to the availability of versatile, compact and efficient fibre based pump sources that could be readily integrated with the microstructured fibre devices into robust instruments, to the point now where the fibre based supercontinuum source has been a major commercial success.

In this series of lectures, I will consider the development of the supercontinuum source from its origin utilizing solid state laser pumping of bulk samples of glass and highly nonlinear materials to the sophisticated all-fibre integrated schemes of fibre based lasers integrated with photonic crystal fibres. The benefit of fibre based operation will be highlighted as will be all the relevant non linear processes contributing to supercontinuum generation and how these can be controlled to provide optimal operation in specific wavelength regions. Currently with silica and germania based fibres, supercontinuum sources efficiently fill the window of transmission 300 nm to 3000 nm and alternative fibres can be deployed to extend this well into the mid infrared. Various pumping regimes will be considered from high power femtosecond pumping to cw pumping of long lengths where supercontinua with average powers in the 100s watts regime have been generated and spectral power densities in excess of 100mW/nm achieved. Techniques to enhance performance, such as dispersion profiling or fibre tapering will also be described.

However, the commercial supercontinuum source does present some experimental limitations such as when high spectral power density is required or where low temporal jitter of the source is essential or where varying and controllable excitation pulse durations are necessary. In these instances it can be beneficial to utilize direct generation in various all-fibre configurations. Consequently I shall also briefly consider mode locked fibre lasers, both in the soliton and normally dispersive regimes, including Raman based devices for broad wavelength coverage, as well as all- fibre optical parametric oscillators and amplifiers and novel high repetition rate sources providing spectral as well as pulse width and repetition rate selectivity.

Reading

G. Genty, S. Coen and J.M. Dudley, J. Opt. Soc. Am. B 24, 1771 (2007)

Recommended reading

[1] J.M. Dudley, G. Genty and S. Coen, Rev. Mod. Physics 78, 1135 (2006)

[2] J.M. Dudley and J.R. Taylor, "Supercontinuum Generation in Optical Fibers," Cambridge University Press, ISBN 978-0-521-51480-4 (2010)

[3] G.P. Agrawal, Chapter 5, “Applications of Nonlinear Fiber Optics” , Academic Press, ISBN 978-0-12-374302-2 (2008)

About J.R. Taylor

Roy Taylor was born in Carrickfergus, N. Ireland in 1949. He obtained a BSc (1stHons) in physics from the Queen’s University of Belfast and commenced his research career at the Queen’s University in 1971. In 1973 he transferred to the Optics Section at Imperial College and obtained his PhD in 1974. After spending two years at the Technical University in Munich he returned to Imperial College in 1977 as a research assistant. He established the Femtosecond Optics Group at Imperial College in 1986 and over his career has published more than 380 papers and co-authored over 400 conference presentations. His work and contributions in various aspects of laser research, photonics, optical fibres and non linear optics has been recognised by the Carl Zeiss Research Award, the Institute of Physics Thomas Young Medal, Imperial College Research Excellence Award and the Royal Society Rumford Medal.

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