Abstract

Optical data storage has advantages over electronic memory in data capacity and access bandwidth. The high bandwidth of optical storage is mainly due to the large access unit (page), perhaps 128 × 128 to IK × IK bits at each read/write cycle [1]. Work is in progress on developing 2-D cell-oriented optoelectronic (OE) devices for short-term optical data storage or buffering, having a typical density of 1 Mbit/cm2 [2]. In this paper, an electrically controlled, optical addressing scheme for random access to a 2-D OE array is presented. The address decoding scheme employs micro laser sources, volume holograms, and a smart pixel array. Approximately 4 log₂J binary patterns are recorded in a volume hologram acting as an optical addressing system. The reconstruction beams from the laser sources regenerate half of the recorded patterns, which overlap at the image plane. Using a thresholding operation implemented by smart pixel devices, a designated storage position can be identified. In this scheme, coding technology is used to achieve a high relative ratio of the first two high intensity levels. The relative intensity ratio is constant and independent of the OE storage size. Using this scheme, the optical buffer can thus tolerate larger noise and non-uniformities.

© 1993 Optical Society of America