MULTIWAVELENGTH PERFORMANCE OF AN APODIZED ACOUSTOOPTIC SWITCH

Use of the acousto-optic switch as a wavelength-routing element in WDM networks is described. The need for deep isolation between wavelength channels has resulted in the search for efficient sidelobe suppressio n techniques such as tapering of the acousto-optic profile by imbeddin g an optical waveguide in one arm of an acoustic directional coupler. The theory of sidelobe-suppression in the optical transmission functio n of a SAW-coupler apodized acousto-optic filter is presented. A low-s idelobe SAW-coupler-apodized AO switch was fabricated and used in a 1. 5 micron multi-wavelength WDM switching demonstration employing four 4 nm-spaced optical channels. Crosstalk was below -19 dB for single wav elength selection and below -15 dB for arbitrary routing patterns, a d ramatic improvement over unapodized AO switches.