Laser sources that emit in the eye-safe wavelength range around two microns are useful for a great number of different applications. Apart from medical applications that benefit from the strong water absorption, there are gas sensing, light detection and ranging (LIDAR), material processing, and various defence related applications . Two micron lasers additionally provide the ideal sources for nonlinear frequency conversion to the mid-infrared wavelength region. Many of these applications require not only high output power and good beam quality but also narrow linewidth operation and high spectral stability. Diode pumped fibre lasers with fibre Bragg gratings (FBG) can fulfil these requirements much better than conventional solid state lasers.
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