On the bistability of parametric generation process

Non-equilibrium steady state transitions in nonlinear parametric generation process are analyzed. When driven by external coherent light in signal and idler beams, the parametric generator exhibits a strongly bistable behaviour. Under certain circumstances, the bistabilities in signal and idler beams mutually compete. From presented analysis, it follows, the competition can in principle be controlled with the input light signals in a way to implement some model of measurement device. In particular, we suggest operation of the nonlinear parametric generator as an all optical comparator, analogous to routinely used electronic devices. (Author)