Nonlinear optical resonators (excited by external radiation) (review)

A review is given of theoretical and experimental investigations of optical resonators excited by an external light beam and filled with a nonlinear medium. An analysis is made of various types of nonlinearities (Kerr, Raman, Brillouin, and quadratic nonlinearities, saturation in a medium of two-level particles) and equations which describe the dynamics of optical oscillations in a resonator, are derived. Descriptions are given of the main properties such as limitation of the transmitted beam intensity, bistability and hysteresis, intensity pulsations, and amplification of amplitude-frequency deviations in the optical beam. Transient processes are also discussed. In the description of the experimental results, not only the resonator parameters and the observed properties are indicated but attention is also paid to identification of the type of nonlinearity. An analysis is also made of hybrid systems in which the nonlinearity is simulated (and deliberately increased) by radioelectronics.