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

A near-infrared methane (CH4) and ethane (C2H6) dual-gas sensor system based on off-axis integrated cavity output spectroscopy was demonstrated. Simultaneous detection of CH4 and C2H6 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 CH4 and 196.4 ppbv for C2H6 were achieved at an averaging time of 1 s. The reported sensor shows potential applications in vehicle-deployed natural gas leakage monitoring.