Photonic technologies have been widely accepted as a way to alleviate bottlenecks in platform-to-platform, machine-to-machine and board-to-board interconnections. Recent breakthroughs in the fabrication of spatial arrays of optoelectronic emitters and detectors and their heterogeneous integration with Si-CMOS electronic chips now encourage the use of optics as an electronic wire replacement technology also at the inter- and intra- Multi-Chip-Module interconnection level.

The main objective for introducing two dimensional photonic pin-outs at this level of the interconnection hierarchy aims at relaxing the bandwidth limitations between these electronic processing modules primarily imposed by fundamental electrical signal propagation issues and the limited number of electrical chip pin-outs. VLSI-photonic interconnection technologies enable this high-aggregate-bandwidth low-latency photonic data transfer over short distances. It can for example be realised through the use of two dimensional arrays of low-threshold Vertical Cavity Surface Emitting Lasers (VCSELs) and high-sensitivity photo-detectors, flip-chip mounted on CMOS circuitry and optically interconnected by beam-shaping and beam-delivering micro-optical modules.

One of the challenges to make this technology practical and viable is the manufacturing of low-cost, chip-compatible, high-precision three-dimensional micro-optical pathway blocks that integrate all the micro-opto-mechanical components necessary to efficiently interface these opto-electronic surface-normal transmitters and receivers.

In the first part of our presentation we review the state-of-the art of photonic interconnects to silicon chips and highlight opto-electronic emitter and receiver arrays, heterogeneous integration technologies, and free-space and guided-wave optical pathway blocks.

In a second part of our talk we present our approach to photonic interconnects to silicon. We focus on design, fabrication and characterization issues of multi-channel free-space optical interconnection modules and demonstrate a prototype component for fire-hose data capacity well into the Tbit/s.cm2 regime. Finally we tackle cost and replication issues of these optical MEMS in semiconductor compatible optical plastics.