Brillouin-based dual-frequency microwave signals generation using polarization-multiplexing modulation

Dual-frequency microwave signals have potential applications in radar and communication systems to improve system integration and signal conversion convenience. Flexible frequency tunability and low phase noise are important factors for dual-frequency microwave signals. This research focuses on improving frequency tunability of dual-frequency microwave signals meanwhile maintaining low phase noise and high spectrum purity. The outputs of two optical injection-locked slave lasers as Brillouin pump signals are employed combining with an integrated polarization-multiplexing modulator to realize orthogonal polarization multiplexing. Stable dual-frequency microwave signals are obtained in an optoelectronic oscillation loop simultaneously. The obtained microwave signals inherit the flexible frequency tunability of Brillouin effect and low phase noise of the optoelectronic oscillator at the same time.