Low Noise W-band Photonic Oscillator

Photonic oscillators are capable of generating spectrally pure radio, microwave and millimeter wave signals by optical means. The oscillators take advantage of a long lifetime optical energy storage element, such as optical delay line or a cavity, to produce the signals. We here show that using a Kerr comb generated in a magnesium fluoride whispering gallery mode resonator with quality factor exceeding a billion one can generate W-band microwave frequency signals with phase noise approaching -120 dBc/Hz at 10 kHz frequency offset. The observation paves the way towards realization of the miniature microwave photonic frequency generators and synthesizers at higher carrier frequencies.