HOLOGRAPHIC OPTICAL INTERCONNECTS FOR VLSI MULTICHIP MODULES

The design of a prototype multichip module utilizing free-space hologr aphic optical interconnects is discussed. This prototype incorporates GaAs laser array chips and silicon CMOS chips which are flip-chip bond ed to the transparent MCM substrate. Computer generated holograms are etched onto the opposite side of the MCM substrate to form optical lin ks between lasers and photodetectors that are integrated onto the CMOS chips. Comparisons are then performed between optical interconnects a nd electrical interconnects showing that for a 5-cm link the dissipate d power can be reduced by at least an order of magnitude, for datarate s in the range of 700 MHz to 4 Ghz, by using optical interconnects.