Instability of frequency degenerate operation in semilinear coherent oscillator with counterpropagating pump waves

Abstract

In semilinear photorefractive coherent oscillator with two counterpropagating pump waves a single-frequency oscillation is transformed into double-frequency oscillation with the increasing coupling strength. Apart from coupling strength the bifurcation point can be affected by changing the pump intensity ratio and cavity losses. The results of experiments with cobalt-doped barium titanate crystals are in good qualitative agreement with the results of computer simulations within the undepleted pump approximation for nonlinear mixing of four plane waves.