Abstract

In this paper, we present the experimental and numerical studies of nonlinear polarization switching in AGaAs and GaAs/AlGaAs multiple quantum well waveguides. In implementing nonlinear polarization switching, the goal is to induce a nonlinear change of linear polarization by π/2 at the output of a waveguide. When the waveguide eigenmodes (TE and TM) are equally excited at a lower power, modal birefringence results in different phase evolution of the two modes, leading generally to elliptical polarization at the waveguide output. In the experiment, a quarter- and a half-wave plates were used to bring the output polarization back to linear, parallel to the horizontal (TE mode) axis. At a high power, the interplay between self-phase modulation, cross-polarized cross-phase modulation, and oscillatory nonlinear coupling changes the output polarization state relative to the low power case. Complete switching is obtained when the polarization at the output is orthogonal to the low power case. In the intermediate case, the output polarization is at some angle relative to the horizontal axis and the output power is shared by the two polarization directions.

© 1993 Optical Society of America