We report for the first time a bidirectional optical backplane bus for a high performance system containing nine multi-chip module (MCM) boards, operating at 632.8 and 1300 nm. The backplane bus reported here employs arrays of multiplexed polymer-based waveguide holograms in conjunction with a waveguiding plate, within which 16 substrate guided waves for 72 (8 x 9) cascaded fanouts, are generated. Data transfer of 1.2 GbUs at 1.3-pm wavelength is demonstrated for a single bus line with 72 cascaded fanouts. Packaging-related issues such as transceiver size and misalignment are embarked upon to provide a reliable system with a wide bandwidth coverage. Theoretical treatment to minimize intensity fluctuations among the nine modules in both directions is further presented and an optimum design rule is provided. The backplane bus demonstrated, is for general-purpose and therefore compatible with such IEEE standardized buses as VMEbus, Futurebus and FASTBUS, and can function as a backplane bus in existing computing environments. Srikanth Nabrajan received the B.E. degree in electronics and communication engineering from the University of Madras, India, in 1989, and the M.S. degree in electrical engineering from the University of Texas at Austin in 1991. He is currently working toward a doctoral degree in the Department of Electrical and Computer Engineering of the University of Texas at Austin. His research interests include the design and fabrication of polymerbased holographic devices for optoelectronic interconnects with emphasis on holographic backplane bus design for computing environments. Cbunhe Zhao received the B.S. degree in applied physics from the National University of Defense Technology, Changsha, P.R.C., in 1988. Currently he is a graduate student working toward his Ph.D. degree in electrical and computer engineering, the University of Texas at Austin. His research interest includes optical interconnects based on holographic gratings, optical backplane bus, and holographic neural networks. Ray T. Chen, photograph and biography not available at the time of publication.

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We present a surface normal optical interconnect with a l-to-12 collinear fan-out. Two types of polymer-based holograms were fabricated to provide a collinear l-to-12 fan-out from guided mode to substrate modes and twelve l-to-l surface normal interconnects. Fluctuation of up to 7.2 dB for the l-to-12 fan-out hologram was observed due to the oscillating and the film saturation effects of the transmission hologram. Diffraction efficiency better than 70% was observed for all the total internal reflection holograms. The result reported herein greatly enhanced optical signal processing capability of guided wave optical interconnects. The advantages of free space optical interconnect, such as global interconnect, three dimension, massive fan-out/fan-in capabilities, and surface normal optical interconnect, can be realized using the demonstrated architecture. The coupling from waveguide to fiber can be realized from the surface rather than the edge of a photonic integrated circuit.

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We report in this paper, an one-dimensional(1-D), 1 Gbit/sec, fully integrated 1-to-lO optical planar bus array. The optical bus is made out of a thin glass substrate in conjunction with an 1-D hologram array, integrated on the surface. Based on the dispersion relation, the angular misalignment can be used to determine the wavelength tolerance of the optical bus, which is a representation of its modulation bandwidth. Using the experimental results of the angular tolerance, which is determined to be 0.50, it can be shown that a wavelength coverage of 42 nm is achievable when this optical bus is used. The corresponding frequency is 7.5 THz.