Abstract

Optical waveguides and waveguide devices formed by incorporating multiple-quantum-well (MQW) layers into the guiding or adjacent nonguiding regions are of particular interest for switching and other signal-processing applications because of their nonlinear properties. In this work, slab waveguides and waveguide couplers are analyzed exactly to determine the propagation constants, indices of refraction, and shapes of the modes supported by structures formed by an arbitrary number of MQW layers of differing composition. A complex index of refraction represents the dielectric and absorptive properties of each layer composing the MQW region; these values are then used in computer simulations that form matrix representations of the field variables to match the boundary conditions between each pair of layers. Thus, the complex propagation constants of each mode of a guiding structure formed by any number of layers are computed without explicitly writing and matching expressions for the fields at each boundary. Values obtained for propagation constants and effective indices of the modes of isolated waveguides and waveguide couplers will be compared with those obtained by means of a variety of approximations that substitute weighted averages of the indicesof the individual layers for the index of the MQW region.

© 1990 Optical Society of America