Accession Number : AD0802670

Title :   COHERENT OPTICAL ARRAY TECHNIQUES.

Descriptive Note : Final rept.

Corporate Author : SPERRY GYROSCOPE CO GREAT NECK NY ELECTRO-OPTICS GROUP

Report Date : AUG 1966

Pagination or Media Count : 78

Abstract : Studies were conducted to determine the feasibility of a coherent optical phased array system. A fully developed transmitter will provide a greater concentration of beam power on distant targets and electronic beam steering. Feasibility was demonstrated by driving two pulsed neodymium glass laser power amplifiers in a Mach-Zehnder configuration with a laser master oscillator. A servo controlled phase shifter in the path of one laser amplifier permitted in-phase recombination of the two amplifier outputs to produce more output than possible with a single amplifier. The phase stabilization provided by the servo functioned only in the period between pump pulses but proved adequate for continued phase alignment throughout the pump period. Measurements of far field patterns of separated output beams from two amplifiers driven by a pulsed master oscillator showed the expected major and minor lobes. At high average pump powers, changes in radiation pattern caused by thermal distortion effects in the laser glass were observed. Such effects were analyzed and determined to be correctable in a fully developed system. Correction for strain birefringence was demonstrated successfully in an experiment using uniaxial crystal plates to simulate thermally induced birefringence.

Descriptors :   *OPTICAL RADAR), (*PHASED ARRAYS, YTTRIUM, ALUMINUM, DOPING, RODS, INTERFEROMETERS, FEASIBILITY STUDIES, LASERS, NEODYMIUM, GLASS, PHASE SHIFT CIRCUITS, GAIN, CRYSTAL OSCILLATORS, NOISE, REFRACTION, GARNET, FLASH LAMPS, PHOTOMULTIPLIER TUBES, TEMPERATURE, POWER AMPLIFIERS, SERVOMECHANISMS, DISTORTION, OPTICAL PUMPING, POLARIZATION, TEST SETS, STABILITY, RARE GASES.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE