Active ring resonance cavity assisted single-mode all-optical microwave oscillator

摘要： A pure optical microwave oscillator with single mode oscillation is proposed and demonstrated. This system has no any electrical microwave devices as well as electro-optic (E/O) and opto-electronic (O/E) conversion. The oscillation frequency is chosen by Brillouin-selective sideband amplification, and the optical envelope detection and feedback modulation are implemented by a semiconductor optical amplifier (SOA). As a high-Q tunable optical comb filter, an active ring resonance cavity (ARRC) is employed to select one oscillation mode within the Brillouin gain region, and consequently a single mode oscillation signal can be generated. In the experiment, a single mode photonic microwave signal with frequency of 10.83 GHz and side-mode suppression ratio of 48 dB is obtained. The measured phase noise is ?88 dBc/Hz@10 kHz. In addition, the tunability is also demonstrated by adjusting the wavelength of the light source.