Quantum statistics and dynamics of Kerr nonlinear couplers

Abstract

We investigate a codirectional nonlinear coupler composed of two Kerr nonlinear waveguides taking into account linear as well as nonlinear coupling. We calculate quadrature, principal squeezing and integrated intensity variances and quadrature uncertainty product, taking into account effects of transmission of light between waveguides in a closed analytical way in rotating-wave approximation. Incident beams are assumed to be coherent. We show that the coupler can exhibit various quantum properties such as collapses and revivals of oscillations, squeezing of vacuum fluctuations and sub-Poissonian photon statistics in single as well as in compound modes. The field can periodically return to a pure state. The dynamics of energy exchange between waveguides, of self-trapping of beams and collapses and revivals are discussed and a possibility of compensation of nonlinear coupling and self-action processes is demonstrated in competition with linear coupling.