The second or the third harmonic generation on a nonlinear film in a Bragg resonator

A resonator formed by nonperiodic Bragg structure and nonlinear film is considered. Effects of the second or the third harmonic generation are theoretically investigated. System of nonlinear equations for amplitudes of time harmonics is obtained. Phenomenon of resonant increasing of amplitude of the higher harmonic caused by combination of nonlinear and Bragg effects is discovered. Reason of instability of numeric algorithm for "optimal" case is revealed. Ways for overcoming this instability are found. Bistable behavior of scattered waves is observed for cubic nonlinearity.