Whispering-gallery mode based opto-electronic oscillators

We present our recent results related to the development of ultra-compact opto-electronic oscillators based on high-Q whispering gallery mode (WGM) resonators. These oscillators operate in X-, Ku-, and Ka-bands and are able to generate spectrally pure RF signals characterized with less than -120 dBc/Hz phase noise at 100 kHz. The floor of the phase noise (<; -140 dBc/Hz) is limited by the shot noise of the signal received at the photodiode. Both tunable and fixed frequency oscillators are demonstrated.