Single chip 8×8 optical interconnect using micromachined free-space micro-optical bench technology

A three-dimensional multi-stage optical interconnection network is proposed for massively parallel processors. The interconnection network employs beam-steering vertical cavity surface-emitting lasers (VCSEL) as space-division switching elements, and micromachined micro-Fresnel lenses as free-space optical elements. The entire switching network is integrated on a Si chip using the free-space micro-optical bench technology (FSMOB). All the optics in the switching network has been prealigned during the design process. The laser arrays and detector arrays are monolithically fabricated on the same smart pixel plane. Two smart pixel planes are mounted face-to-face and optically connected by the Fresnel lens arrays between them. The number of switching stages can be increased by vertically cascading switching arrays, forming a three- dimensional interconnect network. This configuration greatly reduces the physical dimensions of the system, and can be readily scaled up to large switching networks. We have successfully implemented an 8×8 banyan network by cascading two-folded cavity