Description and evaluation of the FAST-Net smart pixel-based optical interconnection prototype

The design, packaging approach, and experimental evaluation of the free-spa ce accelerator for switching terabit networks (FAST-Net) smart-pixel-based optical interconnection prototype are described. FAST-Net is a high-through put data-switching concept that uses a reflective optical system to globall y interconnect a multichip array of smart pixel devices. The three-dimensio nal optical system links each chip directly to every other with a dedicated bidirectional parallel data path. In the experiments, several prototype sm art-pixel devices were packaged on a common multichip module (MCM) with int erchip registration accuracies of 5-10 mu m. The smart-pixel arrays (SPA's) consist of clusters of oxide-confined vertical-cavity surface-emitting las ers and photodetectors that are solder bump-bonded to Si integrated circuit s. The optoelectronic elements are arranged within each cluster on a checke rboard pattern with 125-mu m pitch. The experimental global optical interco nnection module consists of a mirror and lens array that are precisely alig ned to achieve the required interchip parallel connections between up to 16 SPA's. Five prototype SPA's were placed on the MCM to allow the evaluation of a variety of interchip links. Measurements verified the global link pat tern across several devices on the MCM with high optical resolution and reg istration. No crosstalk between adjacent channels was observed after alignm ent. The I/O density and efficiency results suggest that a multi-terabit/s switch module that incorporates global optical interconnections to overcome conventional interconnection bottlenecks is feasible.