A fine-grained dependable optically reconfigurable gate array as a multi-soft-core processor platform

Optically reconfigurable gate arrays (ORGAs) have been developed as high-speed reconfigurable fine grained gate arrays that can accommodate implementation of a multi-soft-core processor. An ORGA's programmable gate array can be reconfigured in nanosecond-order with one of more than 256 reconfiguration contexts. Its high-speed dynamic reconfiguration capability is suitable for dynamically changing the functions of a multi-core processor. In addition to that beneficial feature, ORGAs have high dependability against space radiation since the ORGA can be reconfigured with an error-included configuration context. In this paper, while maintaining its highly dependable capability, a more advanced dependability-increasing technique using a negative logic implementation is proposed. The dependability of data on a holographic memory depends on the number of bright bits or the binary state H included in a configuration context. If the number of bright bits in a configuration context can be decreased, then the configuration dependability can also be increased. The proposed optical configuration dependability-increasing technique of a negative logic implementation can decrease the number of bright bits in a configuration context. This technique can raise the ORGA's configuration dependability level even further. This paper describes an experimental demonstration of the usefulness of the proposed technique.