A channelized broadband and high-resolution microwave instantaneous multi-frequency measurement system based on Fabry-Perot Filter and Stimulated Brillouin Scattering

Abstract

A broadband high-resolution microwave instantaneous multi-frequency measurement (IMFM) system based on a Fabry-Perot filter (FPF) and Stimulated Brillouin Scattering (SBS) is proposed. In the system, the 14-line flat optical frequency comb (OFC) in the first branch is input to dual-parallel Mach-Zehnder modulator (DPMZM) for carrier suppressed single sideband modulation (CS-SSB), so that the microwave signal to be measured is loaded onto the sideband of the 14-line OFC. The FPF is employed for periodic filtering to roughly determine the frequency band of the captured microwave signal. Subsequently, the demultiplexer (De-mux) is utilized to channelize the captured frequency band, which serves as a pump light input to the high nonlinear fiber (HNLF). By setting the center frequency spacing between the OFCs in the second and third branches with the channelized pump light in the first branch is equal to the Brillouin frequency shift, the frequencies of the microwave signal under measurement are determined based on the fine frequency selection characteristic of the SBS effect. This achieves an enhancement in measurement resolution while ensuring measurement bandwidth. Simulation experiments indicate that by adjusting the frequency shifter and center frequency of the FPF, the proposed IFM system can realize measurement ranges of 0.6–13.5 GHz, 13.6–26.5 GHz, and 26.6–39.5 GHz, the measurement resolution is 0.1 GHz, and the measurement error is ±0.05 GHz.