Abstract

Nonlinear directional couplers have attracted considerable attention because of their potential applications in all-optical switching (see, for example, Refs.1 and 2, and references therein). The conventional way of analyzing pulse switching in an evanescent-field nonlinear coupler is based on solving the linearly coupled nonlinear Schrödinger equations.¹,² Recently, it has been found that these equations are valid only when the dispersion properties of the coupling coefficient can be ignored.³,⁴ In many practical situations, however, the coupling-coefficient dispersion can be important and must be included in the analysis.³,⁴ It has been shown, both theoretically³-⁵ and experimentally,⁶ that a dispersive coupling coefficient can cause pulse distortion, or even pulse breakup. In this paper, using a two-core fiber as an example, we first identify the situations under which the coupling-coefficient dispersion is important, and then demonstrate how the coupling-coefficient dispersion affects the switching dynamics of short pulses in a nonlinear coupler.

© 1998 Optical Society of America