介绍了光纤氢传感器的应用背景和工作原理，分析了其中的微镜式传感器。针对在垂直入射、单次反射方式下工作的微镜式光纤氢传感器，提出了多次反射的传感器模型。从金属光反射模型出发，研究了入射角、反射次数对探测灵敏度的影响。论证了通过多次反射来提高传感器探测灵敏度的可行性。

Fiber optic hydrogen sensors are designed to detect hydrogen in flammable and explosive environment. The sensing mechanism is based on the variations of optic properties of a Pd micro-mirror deposited at the output end face. The variations induced in the Pd coating when it absorbs hydrogen can be used to detect hydrogen concentrations in air. Of the fiber optic hydrogen sensors reported so far in the literature,the beam incident on the film is normal and light is reflected only one time. A new model which can increase the detection sensitivity by multiple reflection is reported. The variation of reflection with refraction index is studied,influences related to angle of incidence and times of reflection are also analyzed. The results show that multiple reflection can improve detection sensitivity,which is of 10 times of that with normal incidence when light is reflected 10 times.