<title>Optical backplane bus for multiprocessor-based computing systems</title>

Abstract

The design and architecture of bi-directional optical backplanes with single and multiple bus lines for high performance bus are reviewed and bus systems with one and 2-bus lines at a wavelength of 850 nm are experimentally demonstrated. For optical backplanes with single-bus line, a speed of 1.2 Gbit/sec at a wavelength of 1,3 µm is demonstrated. Arrays of multiplexed holograms are employed, in conjunction with a waveguiding plate within which cascaded fanouts are generated. For the backplane bus system containing multiple bus lines and 9 processor/memory boards, VCSELs (Vertical Cavity Surface Emitting Lasers) and photodetector arrays, such parameters as power budget, misalignment and packaging related issues are discussed. With the introduction of GRIN lenses into the backplane system, it is found that not only can the signal beam from the VCSELs get collimated, but die angular tolerance of the system is greatly enhanced. The optical backplane bus system developed here is transparent to higher level bus protocols, thus can support standard backplane buses such as Futurebus+, Multi-bus II, and VMEbus.