Error Detection and Correction for Optical Memories

Abstract

Abstract : Novel optical data storage technologies, such as holographic memories, can store and retrieve data in the form of two dimensional arrays of bits of pages (page-oriented memories, POMs). It is anticipated that such memories will soon be able to provide the data rates required by high performance systems. However, for this to be possible, data pages must be retrieved free of errors. Because there are several sources of noise in a POM system, the data stored in the memory must be appropriately encoded so that an error correction scheme will be able to remove the errors during retrieval and provide the required bit error rate. In this effort, we identified and classified several sources of errors in POMs. We developed a set of metrics for the evaluation of error correcting codes for POMs and we evaluated several array codes. We developed a simulator, where we incorporated implementations of most of the error generation processes and certain error correction codes. We used the simulator to evaluate and compare different error correction codes and to approximate real POM systems. Finally, we investigated optoelectronic techniques for the parallel implementation of error control schemes in POMs that could achieve the required throughput.