Photonic interconnects to silicon chips

Abstract

A multi-channel free-space micro-optical module for dense MCM-level optical interconnections has been designed and fabricated. Extensive modeling proves that the module is scalable with a potential for multi-Tb/s.cm2 aggregate bit rate capacity while alignment and fabrication tolerances are compatible with present-day mass replication techniques. The micro-optical module is an assembly of refractive lenslet-arrays and a high-quality micro-prism. Both components are prototyped using deep lithography with protons and are monolithically integrated using vacuum casting replication technique. The resulting 16-channel high optical-grade plastic module shows optical transfer efficiencies of 46% and inter-channel cross talks as low as -22 dB, sufficient to establish workable multi-channel MCM-level interconnections. This micro-optical module was used in a feasibility demonstrator to establish intra-chip optical interconnections on a 0.6gm CMOS opto-electronic field programmable gate array. This opto-electronic chip combines fully functional digital logic, driver and receiver circuitry and flip-chipped VCSEL and detector arrays. With this test-vehicle multichannel on-chip data-communication has been achieved for the first time to our knowledge. The bit rate per channel was limited to 10Mb/s because of the limited speed of the chip tester