一种利用双路相移布拉格光栅的快速微波频率测量方案

A Fast Microwave Frequency Measurement Scheme Using Double Channel Phase-shift Fiber Bragg Gratings

采用相移布拉格光栅设计了一种快速微波频率测量方案。通过在上下两支路配置具有不同陷波频率的相移布拉格光栅,再分别与激光源、相位调制器进行融合处理,利用光电探测器输出功率比与待测微波信号频率之间的映射关系建立幅度比较函数,进而实现微波频率测量。理论分析和仿真结果表明,通过调节激光源的载波频率,可改变微波频率的测量范围和测量精度;再结合大范围低精度频率测量和小范围高精度频率测量的两步测量法,可实现高精度的微波频率测量。该方案具有结构简单、测量精度高等优点。

A scheme for fast microwave frequency measurement based on phase-shift fiber Bragg grating(PS-FBG)is designed.In the proposed scheme,two PS-FBGs with different notch frequencies are utilized into the upper and lower channels,in combination with a laser source and a phase modulator(PM),the amplitude comparison function is established by constructing a mapping relation between the output power ratio of both photodetectors and the frequency of the unknown microwave signal,and so the microwave frequency measurement is realized.Theoretical analysis and simulation results indicate that the measurement range and measurement resolution of the microwave frequency can be changed by adjusting the carrier frequency of the laser source.Meantime,the microwave frequency measurement with high resolution can be obtained by joint operation of a large range frequency measurement with a relatively low resolution and a small range frequency measurement with high resolution.The scheme has advantages of simple structure and high measurement accuracy.