Barnes, W.L., Dakin, J.P., Edwards, H.O., Reekie, L., Townsend, J.E., Murray, S. and Pinchbeck, D.
Tunable fibre laser source for methane detection at 1.68µm
At SPIE Conference on Critical Reviews of Optical Science and Technology, United States.
08 - 11 Sep 1992.
Full text not available from this repository.
A tunable fibre laser for spectroscopic gas detection is reported for the first time. The laser is based on a single-mode thulium doped fibre, which can operate at a wavelength around 1.684µm, corresponding to a significant absorption line for methane. The fibre laser was pumped at 786nm, a wavelength which is readily available with AlGaAs laser diodes and an optical threshold power of 43mW was observed. An in-fibre photorefractive grating was used as the wavelength-selective output coupler for the laser. Simultaneous straining and heating of the grating induced a change in lasing wavelength, and a tuning range of up to 2nm was demonstrated. This new tunable light source was configured within a methane detector and absorption spectra were recorded which demonstrate the presence of this gas. The large tuning range of the thulium fibre laser should allow the detection of many gas species with absorption bands in the wavelength region 1.65µm to 2.05µm.
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