A methane telemetry sensor based on near-infrared laser absorption spectroscopy

In order to detect methane leakage accurately and prompt, a methane telemetry sensor is demonstrated based on near infrared absorption spectroscopy and optimized wavelength modulation technology. The distributed feedback diode laser is applied as the light source to cover the selected absorption line of 6046 cm-1 to reduce the interference of CO2 and H2O. The waveform generator and the digital quadrature lock-in amplifier are constructed by the FPGA to produce driving signals and extract WMS-1f and 2f signals. And the ?2f/1f? method is adopted to eliminate the environment influence such as light intensity fluctuations and improve the signal-tonoise ratio. This methane sensor has the characteristics of fast response and strong resistance to environmental interference and has great application prospect.