Accession Number : AD0908350

Title :   Octave Bandwidth Optical Modulator.

Descriptive Note : Final rept. 10 Feb-8 Dec 72,

Corporate Author : LOCKHEED MISSILES AND SPACE CO INC PALO ALTO CA PALO ALTO RESEARCH LAB

Personal Author(s) : Chow, Kungta K. ; Younger, John J. ; Leonard, William B.

Report Date : FEB 1973

Pagination or Media Count : 109

Abstract : This Octave Bandwidth Modulator Study was an advanced development program aimed at the design, development, fabrication, and delivery of two microwave bandpass laser modulators. One modulator was optimized for operation at 0.53 micrometer, the other at 1.06 micrometers. Design goals for the modulators were: a 1-Gbit/sec data rate capability, using a QPSK format; a 90% modulation depth for 0.53-micrometer radiation at a 5-W rf drive power level; and a 75% modulation depth for 1.06-micrometers radiation at a 10-W rf drive power level. The work performed in this study showed that the modulator was capable of handling a 1-Gbit/sec data rate using a QPSK format. In addition, a modulation index of 100% was obtained for 0.53-micrometer radiation at 1.85 W of drive power; this exceeded design goals. For 1.06-micrometers modulation, because of the need to use high optical power to compensate for low-sensitivity photodetectors, a 53% modulation index at a 1.37-W drive level was the best achievable for the presently available low-quality crystals. A further attempt to increase the modulation index for 1.06 micrometers by increasing the drive power resulted in beam distortion and depolarization. However, extrapolation indicated that a 111% modulation index would be achievable when better materials became available. In addition to modulator performance tests, supplementary tasks consisting of the engineering evaluation of major electro-optic crystals, and the design and fabrication of an oven and an electro-optical/thermal control unit, were performed.

Descriptors :   (*MODULATORS, LASERS), INFRARED LASERS, ELECTROOPTICS, OPTICAL MATERIALS, CRYSTALS, INFRARED RADIATION, LITHIUM COMPOUNDS, NIOBATES, BARIUM COMPOUNDS, SODIUM COMPOUNDS, OPTICS.

Subject Categories : Lasers and Masers
      Electrooptical and Optoelectronic Devices
      Optics
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE