Progresses of ultrastable optical-cavity-based microwave source

Abstract

With the progress of science and technology and the continuous improvement of the precision measurement application technology, the technical requirements for the stability and noise level of the ultra-stable microwave source are increasing. Its application range becomes more and more wide, including high performance frequency standard research, network radar development, deep space navigation system, etc. Up to now, the photonic microwave generators based on ultra-stable laser and femtosecond light comb are believed to be the highest microwave frequency source with the highest frequency stability and the relative frequency stability 10-16 in 1 s. This device is also the basis of the application for the next frequency standard (optical frequency standard). Whether the generation of time or most of the precision measurements, the output laser of the optical frequency standard should be transformed into a super stable baseband frequency signal. In this paper, we first introduce the development, current situation and application requirements of ultra-stable photonic microwave source, then we present the principle and structure of the ultra-stable photonic microwave source and the technical development of its components based on the first set of domestic-made ultra-stable microwave frequency sources developed by the National Time Service Center. For the ultra-stable laser, we mainly focus on the research and development of the ultra-stable cavity design, the Pound-Drever-Hall frequency locking technology, and the residual amplitude noise effect rejection. For the optical frequency combs, we mainly focus on the development of laser mode-locking and frequency control technology based on erbium-doped fiber combing system. For the low noise photonic-to-microwave detection and low noise synthesizer techniques, the noise effect rejection of wideband photoelectric detection and the microwave phase noise induced by the amplitude noise of the laser are emphatically introduced. Finally, we summarize and prospect the photonic ultra-stable microwave generation technique.