Microwave Frequency Measurement Using Brillouin Phase-Gain Ratio With Improved Measurement Accuracy

A novel photonics-based technique of microwave frequency measurement (MFM) is proposed and verified. The method is implemented by introducing a parameter called Brillouin phase-gain ratio (BPGR) which combines Brillouin phase shift and Brillouin gain, where BPGR features a linear response to the unknown signal frequency. Moreover, it enables to enlarge the channel bandwidth of frequency measurement relative to the method of applying only the phase shift spectrum slope or gain spectrum slope, and the important problem of pump-power-dependency affecting system performance can be alleviated. The experiment is established to verify its feasibility and the results show that this method is competent for frequency measurement with very high accuracy. In the end, within two frequency bands of linear slope 0.12–0.17 and 10.12–10.17 GHz, the measurement error below 5 MHz is successfully achieved.