Multi-channel free-space intra-chip optical interconnections: combining plastic micro-optical modules and VCSEL based OE-FPGA.

We fabricated and replicated in semiconductor compatible plastics a multichannel free-space optical interconnection module designed to establish intra-chip interconnections on an Opto-Electronic Field Programmable Gate Array (OE-FPGA). The micro-optical component is an assembly of a refractive lenslet-array and a high-quality microprism. Both components were prototyped using deep lithography with protons and were monolithically integrated using a vacuum casting replication technique. The resulting 16-channel module shows optical transfer efficiencies of 50% and interchannel crosstalks as low as -22 dB. These characteristics are sufficient to establish multichannel intra-chip interconnects with OE- FPGAs. The OE-FPGA we used was designed within a European co- founded MEL-ARI consortium, working towards a manufacturable solution for optical interconnects between CMOS ICs. The optoelectronic chip combines fully functional FPGA digital logic with the drivers, receivers and flip-chipped optoelectronic components. It features 2 optical inputs and 2 optical outputs per FPGA cell, amounting to 256 photonic I/O links based on multimode 980-nm VCSELs and InGaAs detectors.