Statistical properties of single-mode oscillations in photorefractive ring resonators

We investigate the statistical properties of the optical field that arises from two-wave mixing in a single-mode unidirectional photorefractive ring resonator. Two cases are considered: additive noise produced by generation-recombination fluctuations in the photorefractive material´s ionized donor concentration and multiplicative noise produced by fluctuations in the cavity detuning and losses. Like the homogeneously broadened two-level laser near threshold, the photorefractive resonator has Gaussian and Rayleigh-like intensity distributions in the additive and multiplicative noise cases, respectively. The equations describing the linewidths associated with the intensity fluctuations for the two cases and those describing the linewidth and frequency shift associated with the amplitude fluctuation in the multiplicative noise case also have the same form as the laser equations. The descriptions of the linewidth and frequency shift associated with the amplitude fluctuation in the additive noise case are, in general, different from those of the laser