Fault tolerance of a holographic storage system

Demand is increasing daily for large storage systems that are useful for devices operating under a radiation-rich space environment, such as spacecraft, space satellites, and space robots. A holographic storage system, which can easily provide large storage capacity, is a candidate for space embedded systems. The holographic storage system, which requires no rotation mechanism, usually consists of a holographic memory material, a laser array, and a photodiode array. Although a holographic memory itself is an extremely robust device for use in a space radiation environment, its associated components are vulnerable to radiation. Such vulnerable devices can cause severe problems by preventing the reading of all holographic memory contents. This is a turn-off failure mode of a laser array. This paper therefore presents a recovery method for a turn-off failure mode of a laser array on a holographic storage system and presents results of its demonstration.