Quantum statistical properties of nondegenerate optical parametric symmetric coupler

In the framework of Hamiltonian formalism the quantum statistical propertie s of an optical field propagating inside a directional coupler operating by nondegenerate parametric amplification are studied. We investigate the eff ect of switching between the input modes and the outgoing fields from the c oupler. Particular attention is paid to two-mode squeezing, the second-orde r correlation function, quasiprobability distribution functions, and photon -number distribution. Incident number and coherent states are considered. I t has been shown that when one of the modes enters the coupler in the Fock state \1] and the other modes are in vacuum states, the coupler can serve a s a generator of a coherent state. Furthermore, regimes for the generation and transmission of squeezed and/or sub-Poissonian light are found.