Abstract

In asymmetric integrated-optic directional couplers, effects of refractive-index nonlinearities can often be observed at lower guided wave powers than in symmetric couplers of the same length. We prepared asymmetric couplers by potassium ion exchange¹ in several Corning filter glasses and studied the dependence of their switching behavior on wavelength, pulse intensity, substrate glass, and waveguide geometry. A finite-element propagating beam method has been used to model the device response. It is necessary to consider effects of saturation due to band filling of optically induced refractive-index change² in both input and output guides to describe the observed switching behavior with this model. Interesting changes in switching behavior can be observed at powers greater than those required to saturate the nonlinearity in one guide or the other. The potential for using composite nonlinear materials such as the filter glasses for all-optical integrated switching and data-processing devices is discussed.

© 1988 Optical Society of America