Transient stimulated Brillouin scattering in a fiber ring resonator and its effect on optical Kerr bistability

Abstract

We numerically investigate the transient interaction between optical Kerr bistability and stimulated Brillouin scattering (SBS) when an intense optical pulse is incident in a short fiber ring resonator. An initial phase detuning of the ring resonator and the difference in the phase shift between the pump wave and the created Stokes wave are taken into account in the three-wave SBS model. The ratio of the Brillouin gain coefficient to the nonlinear refractive index of the fiber, which is termed the relative Brillouin gain coefficient, is used as a key parameter for examining the conditions for obtaining optical Kerr bistability in a fiber ring resonator. The numerical results show that optical Kerr bistability cannot be obtained in a ring resonator made from a conventional fused-silica fiber because of the generation of SBS. However, if other fibers with relative Brillouin gain coefficients at least 1 order smaller than that of fused-silica fibers are used, we can suppress SBS and hence obtain optical Kerr bistability. Moreover, we investigate theoretically and experimentally the dynamics of SBS in a fused-silica fiber ring resonator irradiated by a Gaussian pulse. The relaxation and pulsation in the Stokes signal depend strongly on the initial phase detuning of the ring resonator. The experimental results obtained with a single-frequency pulsed YAG laser agree qualitatively with theoretical predictions.