High performance, miniature hyper-parametric microwave photonic oscillator

We report on the realization of a packaged microwave photonic hyperparametric oscillator based on a crystalline whispering gallery mode (WGM) resonator. The oscillator produces spectrally pure microwave signals in the X frequency band, characterized with single sideband phase noise of -120 dBc/Hz at 10 kHz. We show that self-injection locking mechanism of the laser frequency to an optical WGM is vitally important for the steady operation of the device. We theoretically study dynamics for formation of the optical frequency comb generated by the hyperparametric oscillator and show that the oscillation threshold coincides with the threshold of the comb generation.