Design of a free-space 3-D crossover optical network

A new method is proposed to map an 2-D crossover network into an 3-D spatial structure. It makes use of an 2 × 4 micro-blazed grating array to realize vertical connections and horizontal connections, and provides straight connections using a mirror. A module of the 3-D crossover network integrating a polarizing beam-splitter, half-wave plate, micro-blazed grating array, half silvered mirror, spatial light modulator and mirror, will accomplish the functions of optical signal switching, multicast, and broadcast. The characteristics of this module are switching-transparency, high-speed performance, and easy-integration. It has been proved that this module can be implemented in free spatial optical interconnections and parallel computing systems.