Ultra-low noise microwave frequency generation based on optical frequency comb

Low noise microwave frequency has important applications in radar, long baseline interferometer and other fields. The phase noise of microwave signal generated by optical frequency comb is lower than 100 dBc/Hz at 1 Hz frequency offset and -170 dBc/ Hz at high frequencies (> 100 kHz), which is the lowest in the noise produced by all existing microwave frequency generation technologies. This paper introduces the basic principle of optical frequency comb generating microwave frequency, analyzes and summarizes various kinds of noise of microwave frequency signals and noise suppressing technologies. Then the low noise measuring methods are introduced, and several typical experimental devices generating microwave frequency and the obtained results are described. With the continuous improvement of optical frequency comb and noise suppression technology, microwave frequency source with very low noise will have wider application prospects and application fields.