针对局部放电测量中的光纤法珀传感器, 研究了其工作点稳定和提高灵敏度的参数优化方法.通过改变可调谐激光器的波长稳定了传感器的工作点.用激光器波长调谐范围确定腔长, 令玻璃薄板的反射率为1, 根据单模光纤对高斯光束的耦合特性和多光束干涉原理, 通过迭代算法得出光纤端面的最优反射率.基于波长调谐范围1530~1565nm的可调谐激光器, 制作了自由光谱范围28nm, 腔长43μm, 玻璃薄板反射率大于0.97, 光纤端面反射率0.52的法珀传感器.经实验测试, 法珀腔光损耗为10%, 条纹对比度为1.实验结果表明, 基于可调谐激光器的传感器工作点稳定, 可测试最小局放声压约为1Pa, 达到实用要求.

A fiber fabry-perot sensor for partial discharges measurement was studied on getting stable working points. The parameters of the sensor were optimized to achieve higher sensitivities. The working points could be stabilized illuminated by a tunable laser. For a senor, the cavity length of the sensor was determined by the tuning range of the tunable laser. Then, the reflectivity of the silica film was set to 1. Finally, the reflectivity of the fiber end was optimized by numerical simulations according to Gaussian beams and multi-beam interference theory. In experiments, a sensor was made with 28nm-FSR, 43μm-cavity length, the reflectivity of the silica film is above 0.97, and the reflectivity of the fiber end is 0.52. The losses of the cavity are 10 percent of the total energy. The fringe contrasts of the sensors arrive to 1. The sensor operates steadily illuminated by a tunable laser with 1530nm to 1565nm tuning range. The minimum detectable acoustic-pressure is about 1Pa. The performances of the sensor meet the demand of practical applications.