CH4/C2H6 dual‐gas detection system based on off‐axis integrated cavity output spectroscopy

Abstract A near‐infrared methane (CH 4 ) and ethane (C 2 H 6 ) dual‐gas sensor system based on off‐axis integrated cavity output spectroscopy was demonstrated. Simultaneous detection of CH 4 and C 2 H 6 was performed using two distributed feedback laser diodes with central wavelengths of 1654 and 1680 nm by time division multiplexing (TDM). TDM of the two lasers was realized using a self‐developed master controller based on digital signal processor. Allan deviations of 27.3 parts‐per‐billion in volume (ppbv) for CH 4 and 196.4 ppbv for C 2 H 6 were achieved at an averaging time of 1 s. The reported sensor shows potential applications in vehicle‐deployed natural gas leakage monitoring.