Multi-point, fiber-optic gas detection with intra-cavity spectroscopy

A novel intra-cavity fiber laser system is demonstrated for multi-point gas detection. The laser uses fiber Bragg gratings as wavelength-selective cavity mirrors and a tunable filter to tune the operating wavelength to the Bragg wavelength of a selected Bragg grating. The Bragg wavelengths of the gratings are chosen to be aligned to different absorption lines of a gas or gases, allowing gas concentrations at multiple locations to be determined.