Simultaneous measurement of gas composition and concentration combined fiber cavtiy ringdown and frequency-shifted interferometry

摘要

A fiber cavity ringdown gas sensing system combined with frequency-shifted interferometry (FSI) for the simultaneous measurement of gas composition and concentration was proposed. With this technique, the loss spectrum of target gas was experimentally achieved by scanning the wavelength of laser source. And its characteristic absorption wavelength agreed well with that of acetylene provided by the Hitran database, which indicates the target gas was exactly the acetylene sample. The gas concentration was also measured simultaneously with a standard deviation of +/- 0.03%. The corresponding detection sensitivity was 263.48 ppm, which can be further improved by using the gas cell with smaller insertion loss. The experimental results show that the proposed gas sensing system has the advantages of low-cost, good linear responses, high stability and high sensitivity.