Gas Sensing Technique Based on Fiber Laser Built-in Thermal Lens Spectroscopy Sensor

Abstract

A gas sensing technique based on a fiber laser built-in all-fiber thermal lens spectroscopy sensor is proposed. Both ends of the fiber are terminated by two fiber bragg gratings, which function as a “reflection mirror” so that Fabry–Perot intracavity is composed. This intracavity contains the thermal lens sensing head, the erbium-doped fiber, and the wavelength tunable band-pass filter. This article describes the performance of a fiber laser built-in all-fiber thermal lens spectroscopy sensor whose sensitivity is demonstrated and compared with our previous sensor; sensing characteristics for these sensors are also discussed.