Accession Number : ADA274249

Title :   High-Speed, High-Density, Coherent Time-Domain Optical Memory

Descriptive Note : Final rept. 1 Sep 90-31 Aug 93,

Corporate Author : SRI INTERNATIONAL MENLO PARK CA

Personal Author(s) : Kachru, Ravinder ; Shen, Xiao-An

PDF Url : ADA274249

Report Date : NOV 1993

Pagination or Media Count : 53

Abstract : The objective of this research was to quantitatively evaluate the concept of time-domain optical memory (TDOM) using the hole-burning mechanism. The TDOM concept offers both high speed and high memory density. The advantage of TDOM over traditional semiconductor memory is its inherent parallelism, which allows data to be stored and retrieved from the memory at much higher speed. The practical success of the proposed memory, therefore, depends critically on-among other issues-the storage, retrieval, and processing of images. In addition, new data storage techniques are needed to implement a practical memory. The last three years of this research program have focused on (1) development of new phase modulation techniques to enhance the storage, retrieval, and integrity of the stored information; (2) experimental studies of image storage and phase conjugate retrieval; (3) Image processing; and (4) practical holographic storage of images by using the hybrid time-frequency approach. Specifically, SRI demonstrated data encryption by phase modulating the read and write pulses. Image correlation and convolution was demonstrated and its implication for pattern recognition examined. Finally, this laboratory demonstrated high- fidelity random access and retrieval using holographic storage in Pr3+: YA103 with a single-frequency ring laser. These experiments have clearly demonstrated the practical viability of TDOM with existing technology. In the next stage of the research, the performance Issues such as bit-error-rates, signal-to-noise ratios, and laser stability need to be addressed.

Descriptors :   *OPTICAL STORAGE, *TIME DOMAIN, FREQUENCY, RING LASERS, IMAGE PROCESSING, RATIOS, STABILITY, HIGH VELOCITY, SIGNAL TO NOISE RATIO, COHERENCE, RATES, SEMICONDUCTORS, LASERS, CORRELATION, ECHOES, PULSES, SIGNALS, IMAGES, ERRORS, CONVOLUTION, PHASE MODULATION, HIGH DENSITY, PATTERNS, ACCESS, PHOTONS, RECOGNITION, PATTERN RECOGNITION, NOISE, MODULATION

Subject Categories : Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE