Low Noise Radiofrequency Oscillators Based on Optical Microcavities

Low noise stable oscillators impact many areas of since and technology ranging from metrology and navigation to medicine and communications. Measurement techniques involving phase and frequency variations belong to the most accurate and sensitive ones. In communications transmitted information is encoded as modulation of amplitude, phase, or frequency of a carrier wave. Spectral purity of the wave determines the number of distinct data channels that may be transmitted. The frequency of the carrier wave defines the maximum bandwidth of the signal. Availability of high quality (Q) factor resonators is critical for building the oscillators with high spectral purity. As the quality factor of electronic devices generally degrades with the carrier frequency increase, radiofrequency (RF) photonic oscillators involving high-Q optical cavities come in the spotlight. Since an optical frequency exceeds the RF by several orders of magnitude, the photonics devices enable generation of the RF signals with spectral purity independent on the carrier RF value. In this presentation we review recent achievements in the development of the RF photonic as well as optical oscillators based on nonlinear optical microcavities and cover several peculiar effects associated with the devices including frequency noise eating and time crystal generation.