Optical switching of many wavelength packets: A conservative approach for an energy efficient exascale interconnection network

A conservative approach to construct an energy efficient Exascale interconnection network to keep using packet based programs and programming styles used on super computers and in data centers today is to use high speed and energy efficient packet switches. As experimental electrically controlled optical packet switches with practically large number of fiber delay line buffers are already implemented with many wavelength packets, their applicability for Exascale interconnection network is studied. It is shown that, with conservative technologies readily available today, interconnection networks with Exascale bisection bandwidth (effectively 0.53Ebps at 60% load) can be constructed from elementary 4 by 4 buffered (packet drop probability of 0.0089% at 60% load) optical packet switches with effective end to end (excluding power for EO and OE at the both ends outside of the interconnection networks) power consumption of 1.49pJ/bit and 5.3pJ/bit using butterfly and Benes topologies, respectively.