Research on the application of optoelectronic oscillators in airborne radar operational environment

The spectral purity of transmitted signal plays the key role in the application of modern airborne radar. Microwave photonic signal sources based on photoelectric oscillators (OEO) can directly generate high frequency local oscillator signal, and its phase noise level is significantly better than that of traditional microwave local oscillators. Currently, there are limited researches on the application of the photoelectric oscillator in the airborne practical environment, while the operational environment of the airborne radar is extremely harsh. This will hinder the practicality of the photoelectric oscillator in the airborne radar. In this paper, the key role of phase noise in airborne radar scene detection is analyzed first. The influence of different signal forms on the phase noise of the transmitted excitation signal in radar is calculated, and the principle of reducing phase noise to improve the detection performance of airborne radar is summarized. Based on the design framework of the optical oscillator, the phase noise level of the optical oscillator in the airborne vibration environment is analytically analyzed and numerically simulated. The physical model and empirical formula of the influence of the phase noise of the optical oscillator in vibrational environment are established. Finally, the validity of the theory of phase noise deterioration in the vibrational environment is verified by the vibration-test-platform experiment. Combined with the test results, some suggestions for improving the design of the photoelectric oscillator for airborne radar in the actual combat environment are summarized. This work lays a good foundation for the application of photoelectric oscillator in airborne radar.