What do you want your fibre laser to do?
First demonstrated in 1961, the fibre laser has developed into an efficient, compact, high-power tool that is dominating manufacturing and engineering applications. For the majority of laboratory and commercial based instrumentation, more modest watts-level average powers are required, however, often extensive versatility in pulse width and repetition rate are demanded, together with wavelength operation outside the traditional spectral ranges provided by the Yb, Er and Tm-doped silica based systems.
Temporal and spectral diversity is provided by the master-oscillator, power fibre amplifier (MOPFA) in combination with subsequent nonlinear conversion in optical fibre or in fibre coupled crystals, giving rise to highly efficient, fibre-integrated compact sources that can be readily incorporated into instrumentation. Probably the best example of spectral versatility is that achieved by the supercontinuum source, which covers the complete window of transmission of silica fibre, from ~320 nm to 2300 nm with spectral power density up to ~50mW/nm. Such sources are finding broad application in imaging technologies. However, other applications require greater spectral power density in specific excitation pulse shapes with extended wavelength capability. Multi-watt average power visible schemes will be described based upon fully integrated, frequency-doubling of MOPFA pumped fibre Raman generators.
In the mid infra-red, where application extends from remote sensing and polymer machining to counter-measures or pollution monitoring in the so called molecular
fingerprint region, extended tunability of high average power sources based upon difference frequency generation of rare earth and Raman based MOPFA instruments will be described.
Roy Taylor is Professor of Ultrafast Physics and Technology at Imperial College London. He is an experimental physicist in the field of fibre based non-linear optics and established the Femtosecond Optics Group at Imperial in 1986. His interests are in the generation and application of ultrashort pulses to fundamental nonlinear processes, primarily optical fibre based, with the objective of making versatile systems of commercial interest in various applications.