INTERMEDIATE-STATE-ASSISTED OPTICAL COUPLER

摘要

An optical coupler, for coupling two optical waveguides (50, 60), and an optical switch based on the optical coupler. The indices of refraction of parallel sections of the two waveguides (50, 60) are reversibly perturbed periodically in space by imposing a mechanism (58, 68, 59, 69) to couple low order modes in the two waveguides via a high order mode common to the two waveguides. The waveguides are thus coupled with a beat length that may be five or more orders of magnitude shorter than it would be without the periodic perturbations.