SURFACE-NORMAL 3X3 NONBLOCKING WAVELENGTH-SELECTIVE CROSSBAR USING POLYMER-BASED VOLUME HOLOGRAMS

We present a 3X3 surface-normal wavelength-selective crossbar using po lymer-based volume holograms. A prototype device is demonstrated using the center wavelength of 775 nm and Delta lambda=10 nm. Employment of 1/4-pitch graded-index rod lenses reduces the required nine wavelengt hs to three while maintaining the 3X3 interconnects. The diffraction e fficiencies of 75%, 83%, and 75% are experimentally confirmed for wave length 765, 775, and 785 nm, respectively, Surface-normal configuratio n eliminates the conventional edge-coupling scheme which is vulnerable in a harsh environment. A 3X3 crossbar is demonstrated with a two-way system insertion loss less than 3 dB and channel-to-channel cross tal k less than 20 dB. (C) 1996 American Institute of Physics.