Abstract

Waveguide structures which utilize dielectric and quantum confinement nonlinearities in the guide or cladding are currently receiving great attention due to the potential for fast response times and switching¹. We consider here the case of planar waveguide structures consisting of alternating layers of Ga_l-xAl_xAs with varying aluminum concentration in a stepwise fashion to form the waveguide and the cladding, but with alternate layers of etched GaAs/Ga_l-xAl_xAs multiple quantum well material as remote cladding. The latter thus form a remote cladding composite material for electronic quantum confinement in GaAs quantum dots. Using a generalization of a method discussed by Walpita², the effects of the nonlinear cladding on the modes of the waveguide are studied as a function of the thickness of the nonlinear layer, the intensity of the electric field, and the change in the refractive index due to the variation in the aluminum concentration. The effects on the propagation of the electromagnetic field due to the nonlinear cladding are studied under the slowly varying envelope approximation using a variation of the Crank-Nicholson method³ to solve the nonlinear Schroedinger equation. Results will be presented for a model nonlinear (intensity dependent) dielectric constant with absorption.

© 1988 Optical Society of America