We propose a quantum-mechanical model of a nonlinear beam splitter having third-order nonlinearity. We show that nonclassical features, such as squeezing and sub-Poissonian photon statistics of optical fields, can be generated in the output when we mix coherent light beams via such a nonlinear beam splitter.
We investigate both codirectional and contradirectional nonlinear couplers composed of two nonlinear waveguides operating by second- and third-order nonlinear optical processes. We take into account possible mismatches inside the waveguides and between them. Quantum statistical characteristics, such as photon number distribution, its factorial moments, quadrature and integrated intensity variances and quadrature uncertainty product demonstrate generation and transmission of nonclassical light in nonlinear couplers. Incident beams are assumed to be coherent, squeezed and mixed with external noise. Nonclassical behavior of beams generated by the nonlinear waveguides can be transferred to linear waveguides and controlled by linear signal and by linear and nonlinear mismatches. In the contradirectional regime of propagation asymptotic nonclassical states can be obtained.
In this Letter, we present a simple and versatile scheme for enhancing the nonclassical properties of light states using only linear optics and photodetectors. By combining a coherent state |α〉 and an arbitrary pure state of light |ϕ〉 (excluding coherent states) at two beam splitters, we show that the amplitude α of the coherent state can be tuned to filter out specific Fock components and generate states of light with increased nonclassical features. We provide two examples of input states and demonstrate the effectiveness of our scheme in enhancing the sub-Poissonian statistics or the quadrature squeezing of the output states.
The familiar input-output relations for an optical beam splitter are generalized to allow for linear absorption by the medium forming the mirror. Beam-splitter losses generally affect the noise levels detectable in experiments involving nonclassical light. When employed to investigate two-photon interference effects, a lossy beam splitter can lead to apparent nonlinear absorption, which, in the most extreme case, leads to either both or neither of the photons being absorbed. The degree of second-order coherence of antibunched light can be maintained on transmission through the beam splitter but any amplitude squeezing in the incident light is degraded.
Some years ago Katriel and Solomon [1] described applications to the characterization of the photon statistics of nonideal lasers, nonclassical light, and deformed photon states using f -deformed coherent states. In this letter, we study the effect of a beam splitter on these nonlinear coherent states. We find that these states are useful for generating quantum entanglement as the deformation parameter gets farther form the unity and for strong input field regimes. The results are confirmed through the Werhl entropy.