Progress in Optical Interconnects for Data Communication — Bringing Light to the Board, Backplane, and Intra-Boxes

The off-chip electrical interconnects for high speed and high I/O processors have become increasingly complex and costly. Data transfer rates exceeding gigabits per second are common in high performance computer systems. A cost-effective wide-band interconnect between chips, modules, boards, backplane, frames and cabinets has become increasingly critical in the system design. This paper reviews several major R&D programs that have taken place in the last few years in an attempt to develop a viable optical interconnect solution for short-haul data communication applications. In particularly, the technical advances developed under the POINT (Polymer Optical Interconnect Technology) program are described. The POINT program, focusing on developing affordable optoelectronic packaging and interconnect technologies for board and backplane, was a collaborative R&D effort among GE, Honeywell, AMP, AlliedSignal, Columbia University and UCSD, sponsored by DARPA/ETO. Several key technologies and processes developed for reducing optoelectronic packaging and interconnect cost are reported in this talk-specifically, the development of: (a) a plastic VCSEL array packaging technology employing planar and batch fabrication processes for low-cost manufacturing, (b) a high density optical interconnect using polymer waveguides for board and backplane applications, (c) passive alignment techniques for reducing the recurrent cost in an optoelectronic assembly, and (d) low-loss optical polymer materials for optical interconnects.