Free-space board-to-board optical interconnections

In computing, trends toward parallel processing, multiprocessor computers, higher operating speeds, and larger as well as denser very large scale integrated (VLSI) circuits have provided an impetus for the development of advanced interconnection technology. Optical interconnections have been of interest at all levels in digital computers for applications between mainframes, modules, boards,1 chips,2-4 and even points within a chip.5 Optical interconnections are viewed both as a technology to be used in conjunction with electrical interconnections and electronic logic circuits and as an enabling technology for optical computers.6 These interconnections are expected to provide advantages in situations that require high speed, high interconnection density, high connectivity, and long distance. This paper is a review of Lincoln Laboratory work on free-space board-to-board optical interconnections.7