Accession Number : ADA182129

Title :   Analysis and Experimental Implementation of Optical Beamformers.

Descriptive Note : Memorandum rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Griffin,Richard D ; Rolsma,Peter B ; Lee,John N

PDF Url : ADA182129

Report Date : 20 May 1987

Pagination or Media Count : 53

Abstract : Most modern beamformers are implemented on a digital computer. This report examines the potential for analog optical beamforming systems to meet the proposed requirements. The report lists various beamforming algorithms and their calculational complexity; a list of the strengths and weaknesses of digital implementations is also included. Various general algorithms for time and frequency domain optical beamforming are then described. Special emphasis is placed on the importance of designing efficient interfaces between analog optical and electronic systems and digital systems. Details of three implementations of optical beamformers are presented: cross bar and partial sum time domain beamformers, and a vector matrix frequency domain beamformer. Without further research it is not possible to determine the maximum practical capability of an optical beamformer, but frequency domain optical beamforming systems look promising for systems requiring large numbers of beams. The experimental optical vector matrix processor has been designed, constructed, and configured to perform frequency domain beamforming at a rate of 2 x 10 to the 9th power 8-bit multiplies/sec. It also is likely that optical beamformers can meet the low power and size requirements in certain applications such as on board processing for sonobuoys employing hydrophone arrays: an architecture has been developed with potential power consumption of 20mW. Early architectures were implemented using commercial liquid crystal display devices but their response times proved inadequate. The more promising architecture uses fiberoptic couplers and a photodetector array/CCD MUX and is currently in the breadboarding stage of development.

Descriptors :   *BEAM FORMING, *SONAR EQUIPMENT, *OPTICAL EQUIPMENT, ALGORITHMS, ANALOG SYSTEMS, OPTICAL EQUIPMENT, DIGITAL SYSTEMS, EFFICIENCY, INTERFACES, FREQUENCY, ELECTRONIC EQUIPMENT, DIGITAL COMPUTERS, ARCHITECTURE, COUPLERS, FIBER OPTICS, BREADBOARD MODELS, ELECTROOPTICS, CHARGE COUPLED DEVICES, MULTIPLEXING, BEAM STEERING, LIQUID CRYSTAL DISPLAY SYSTEMS, OPTICAL PROPERTIES, ENERGY CONSUMPTION, SONOBUOYS, ARRAYS, HYDROPHONES, LOW POWER, PHOTODETECTORS, TIME DOMAIN

Subject Categories : Electrooptical and Optoelectronic Devices
      Optics
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE