基于激光瞬态特性的内腔气体浓度光纤传感器

报道了一种基于掺铒光纤激光器瞬态特性的内腔吸收式气体浓度传感器.介绍了掺铒光纤激光器内腔吸收谱的基本原理,以及激光激射延迟时间与气体浓度的关系.用光纤环全反镜和光纤Bragg光栅构成F-P线形腔,通过调节光栅的反射波长,使激光激射波长落在乙炔的一个较强的吸收峰1532.83 nm上.通过测量激光激射延迟时间可以获得气体的浓度.实验证实了方案的可行性,该装置的灵敏度可以达到10×10~(-6).

Intra-cavity fiber sensor for measuring gas concentration based on laser's transient regime

An intra-cavity fiber sensor for measuring gas concentration is reported,which is based on the transient regime of a Er-doped fiber laser.The principle of intracavity laser absorption and the relationship between gas concentration and the laser build-up time is outlined.A Sagnac fiber loop and a FBG that also acts as the sensing element form the linear fiber laser cavity.By adjusting the central wavelength of the grating mirror,the oscillating wavelength is set to 1531.56 nm,which is a strong absorption peak of C_2H_2.The gas concentration can be obtained by measuring the laser build-up time.In the present experiment,the sensor's sensitivity can reach 10×10~(-6).