Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser

A correlation spectroscopy (COSPEC) based on a multi-wavelength fiber laser is first proposed for the detection of gas concentration. The lasing wavelengths are selected to match several characteristic absorption peaks of the gas under test, and the gas concentration is easily measured by correlating it with the reference gas. The present method is immune from the instability of the light source and the influence of other gases. The concentration measurement of CH is demonstrated in the experiment in its near-infrared dominant absorption region. The technique has prospects for simultaneous detection of multiple gases, and the measurement of mixed gases of CH and CO is also analyzed.