Abstract

In all-optical switching the required phase shift is produced by the light itself. Typically this phase shift has been achieved via the intensity-dependent refractive index, i.e., third-order nonlinearities. But recently the fact that the so-called cascaded second-order nonlinearity can imitate the third-order nonlinearity was proved experimentally.¹ A phase shift in the cascaded nonlinearity is obtained through the energy exchange between a fundamental light beam and its second harmonic. In the Mach-Zehnder interferometer we need a π-induced phase shift for switching, which is half of the required phase shift compared to directional coupler. Previously we demonstrated switching action using a LiNbO₃ channel waveguide in one of the interferometer, and air in the other.² Here we report high-contrast switching in a fully integrated asymmetric Mach–Zehnder interferometer.

© 1996 Optical Society of America