Design Considerations for a Semipermanent Optical Memory

Abstract

The potential of high-speed optical memories using electro-optic or acousto-optic light deflection for address selection is examined. It is shown that for such memories the total memory capacity decreases as the third power of the addressing rate and that capacities in excess of 108 bits are feasible with a random access rate of 106 addresses/sec. A specific semipermanent memory design is then described which uses a laser light source, an acoustic xy light deflector and an array of 104 holograms as information storage elements. Each storage element contains 104 bits which appear as a pattern on a semiconductor read-out matrix when the storage element is illuminated through the xy deflector. Accordingly, the system has a total capacity of 108 bits with an access time of less than 10 μsec.