The operation of a new all-optical switch potentially capable of ultrafast exchange of information between two orthogonally polarized light beams with identical or slightly different wavelength and comparable intensity are described in terms of two interacting nonlinear couplers. We consider the four lowest-order modes (including polarization) of a dual-core optical-fiber nonlinear coupler. We show how the output power ratio between two modes with identical linear polarization propagating in parallel cores can be controlled in an incoherent manner by the presence of another orthogonally polarized light beam by virtue of the optical Kerr effect. An interesting new feature is that, owing to the spatial instability of the coupled-mode equations, when the fiber is sufficiently long (e.g., two linear coupling lengths), a relatively weak pulse is capable of completely switching out a stronger (ideally square) orthogonally polarized pulse. We find that nonlinear coupling may lead to spatial stochasticity and chaotic power-dependent switching whenever the input conditions are given in the vicinity of the normal (or array) modes of the coupler. Conversely, when the modes of the individual cores are excited, the solutions turn out to be regular for almost any input power level.
© 1988 Optical Society of America
Original Manuscript: August 14, 1987
Manuscript Accepted: October 30, 1987
Published: February 1, 1988
S. Trillo and S. Wabnitz, "Coupling instability and power-induced switching with two-core dual-polarizations fiber nonlinear couplers," J. Opt. Soc. Am. B 5, 483-491 (1988)