Compact CH_4 sensor system based on a continuous-wave, low power consumption, room temperature interband cascade laser

摘要

A tunable diode laser absorption spectroscopy-based methane sensor, employing a dense-pattern multi-pass gas cell and a 3.3 μm, CW, DFB, room temperature interband cascade laser (ICL), is reported. The optical integration based on an advanced folded optical path design and an efficient ICL control system with appropriate electrical power management resulted in a CH_4 sensor with a small footprint (32 × 20 × 17 cm~3) and low-power consumption (6W). Polynomial and least-squares fit algorithms are employed to remove the baseline of the spectral scan and retrieve CH_4 concentrations, respectively. An Allan-Werle deviation analysis shows that the measurement precision can reach 1.4ppb for a 60s averaging time. Continuous measurements covering a seven-day period were performed to demonstrate the stability and robustness of the reported CH_4 sensor system.