We propose quantum-mechanical model of a beam splitter with second-order nonlinearity and show that non-classical features such as squeezing and sub-Poissonian photon statistics of optical fields can be generated in output fundamental and second harmonic modes when we mix coherent light beams via such a nonlinear beam splitter.
We derive the quantum-statistical properties of light beams in nonlinear symmetric and asymmetric couplers composed of linear waveguides and a nonlinear waveguide operating by the second-harmonic generation. This device can exhibit non-classical behaviour in single and compound modes and produce squeezed and/or sub-Poissonian light. Power solutions are obtained up to the twelfth order adopting a symbolic computer method. In addition, new higher-order results for the asymmetric coupler are presented.
Statistical properties of light generated in nonlinear optical couplers are discussed. Methods suitable for the description of non-classical properties of light are mentioned; special attention is paid to generalized superposition of coherent fields and noise. Regimes suitable for non-classical light generation in various types of nonlinear couplers based on second-harmonic and second- subharmonic generation, optical parametric processes, Kerr effect as well as Raman and Brillouin processes are analyzed. Special attention is devoted to the generation of light with sub-Poissonian statistics, squeezed light, and light in purely quantum states. Role of real effects like damping of optical fields and phase mismatches is also discussed.
We derive the quantum statistical properties of light beams involved in an asymmetric nonlinear coupler composed of a linear waveguide and a nonlinear waveguide operating using second harmonic generation. Examining quadrature and integrated intensity fluctuations, photon number distribution, reduced factorial moments and the uncertainty product, we demonstrate non-classical behaviour of single and compound modes. We show that squeezing of vacuum fluctuations, sub-Poissonian photon statistics and oscillations in photon number distribution created by nonlinear dynamics can be transferred to the linear signal mode. Also effects of non-classical incident beams and smoothing effects of external noise are demonstrated.