FREE-SPACE DIGITAL OPTICAL-SYSTEMS

Within the past 15 years there has been significant progress in the de velopment of two-dimensional arrays of optical and optoelectronic devi ces. This progress has, in turn, led to the construction of several fr ee-space digital optical system demonstrators. The first was an optica l master-slave flip-flop using Hughes liquid-crystal light valves as o ptical logic gates and computer-generated holograms as the gate-to-gat e interconnects. This was demonstrated at USC in 1984. Since then ther e have been numerous demonstrations of free-space digital optical syst ems including a simple optical computing system (1990) and five switch ing fabrics designated System(1) (1988), System(2) (1989), System(3) ( 1990), System(4) (1991) and System(5) (1993). The main focus of this p aper will be to describe the five switching fabric demonstrators const ructed be AT&T in Naperville, IL. The paper will begin with an overvie w of the SEED technology which was the device platform used by the dem onstrators. This will be followed by a discussion of the architecture, optics, and optomechanics developed for each of the five demonstrator s.