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A novel single frequency stabilized Fabry-Perot laser diode at 1590 nm for gas sensing
Vincent Weldon1, Karl Boylan, Brian Corbett
1Physics Department, Trinity College, University of Dublin, Ireland. vweldon@tcd.ie
Abstract:
A novel single frequency stabilized Fabry-Perot (SFP) laser diode with an emission wavelength of lambda = 1590 nm for H2S gas sensing is reported. Sculpting of the multi-mode spectral distribution of a FP laser to achieve single frequency emission is carried out using post growth photolitographic processing of the device. The resulting longitudinal-mode controlled FP laser has a stabilized single frequency emission with a side mode suppression ratio (SMSR) of 40 dB. The application of this device to spectroscopic based H2S sensing is demonstrated by targeting absorption lines in the wavelength range 1588 < or = lambda < or = 1591 nm. Using wavelength modulation spectroscopy (WMS), a low detection limit of 120 ppm x m x Hz(-1/2) was estimated while targeting the absorption line at 1590.08 nm. These initial results demonstrate the potential of the stabilized FP laser diode at this wavelength as a tunable, single frequency source for spectroscopic based gas sensing.