Methane sensing with a novel micromachined single-frequency Fabry-Perot laser diode emitting at 1331 nm

Spectroscopic-based gas sensing is demonstrated using micromachined single-frequency Fabry-Perot (FP) laser diodes emitting at 1.331 μm with a side mode suppression ratio of greater than 24 dB over a significant emission wavelength tuning range. The utility of these novel mode controlled FP lasers for spectroscopic detection of gases is assessed by investigating the methane-absorption band in the 1.33 μm region. By probing the narrow linewidth R2 rotational absorption line, we demonstrate a low gas detection limit of 28 ppm/spl middot/m and confirm the suitability of micromachined lasers in such applications.