Nonlinear prism coupler: Approximate theory and comparison with rigorous analysis

A prism coupler filled with nonlinear Kerr-like material is studied theoret ically. A simple, approximate analysis is developed to predict its behavior in both linear and nonlinear optics. In a wide range of incident amplitude magnitude, optical bistability and multistability are found. As far as fie ld map not undergo drastic change, the simpler approximate theory is able t o quantitatively analyze both prism couplers and waveguide in nonlinear opt ics and to study such effects as nonlinear phase shift, existence of nonlin ear asymmetric modes in symmetric environments, bi-and multistability. The predictions of the analytical theory are compared with the results obtained via numerical integration of Maxwell equations and they agree quite well.