High frequency photonic microwave oscillators based on WGM resonators

This paper studies the applications of novel photonic microwave oscillators containing high-Q whispering gallery mode (WGM) resonators intended to produce low noise high frequency MW signals ranging from X-band to W-band. We theoretically compare the fundamental as well as practical restrictions on the performance of both an optical hyper-parametric oscillator based on a nonlinear high-Q WGM resonator and an "oscillator" based on two lasers locked to the same linear WGM resonator to produce stable MW beat signals. Finally, we report on a proof of the principle experiment where we realized the hyper-parametric oscillator generating ∼ 10 GHz signals with 200 Hz linewidth and -110 dBc/Hz noise floor at 1 MHz from ∼ 10 GHz carrier.