Bandwidth-Extended Microwave Frequency Measurement System Based on Stimulated Brillouin Scattering Effect

A photonic-assisted approach for ultra-wideband frequency measurement based on stimulated Brillouin scattering and a chirped optical pulse sequence was proposed. The system leverages the distinct responses of different sidebands within the chirped pulse sequence to an unknown signal, thereby achieving ultra-broadband microwave frequency measurement. The proposed architecture is simple and overcomes the bandwidth limitations of the traditional chirped signals. With a sweep frequency range of 20 GHz, the theoretical instantaneous bandwidth for frequency measurement reaches 78.8 GHz, covering a range from 10.6 GHz to 89.4 GHz. Experimentally, the measured instantaneous bandwidth is 58.4 GHz, with a frequency measurement range of 10.6 GHz to 69 GHz and a root mean square error of 11.4 MHz within this range. To the best of our knowledge, this system achieves unprecedented instantaneous bandwidth for high-precision microwave frequency measurements. The exceptional performance of this system holds significant potential for applications in satellite communications, radar systems, and other fields.