Electro-optic modulation on nonlinear phase shift and fundamental transmission in quasi-phase-matched second-harmonic generation

Nonlinear phase shift and transmission experienced by a beam at the fundamental frequency during electro-optic modulated quasi-phase-matched second-harmonic generation are studied. Numerical results indicate that the nonlinear phase shift of fundamental wave shows a difference of π, while fundamental transmission is controllable only by applying a DC electric field along z-axis. The above effect can be implemented on high-contrast optical switching devices such as Mach–Zehnder push–pull device. The relationships between the characteristic (peak and dip) electric fields and the initial pump intensity are also discussed.