Generation of entangled states by a nonlinear coupler pumped in one mode induced by broadband laser

Kerr nonlinear coupler consists of two nonlinear oscillations in which one of them linearly excited by an external classical field. This is assumed to be decomposed into two parts: a coherent part and a randomly fluctuating chaotic component that is a δ-correlated, Gaussian, Markov, stationary process (white noise). We solve a set of coupled stochastic integro-differential equations involved in the problem with all initial conditions and obtain analytical formulae for the complex probability amplitudes of finite n-photon Fock states. Especially, our study shows that the system is also able to generate maximally entangled states and, as a consequence, the coupler discussed behaves as a two-qubit system and the results compared with those derived previously in the literature.