Accession Number : ADD014315

Title :   Apparatus and Method for Minimizing Polarization-Induced Signal Fading in an Interferometric Fiber-Optic Sensor Using Input-Polarization Modulation.

Descriptive Note : Patent Application, Filed 21 Jul 89,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Kersey, Alan A ; Marrone, Michael J

Report Date : 21 Jul 1989

Pagination or Media Count : 35

Abstract : An apparatus for minimizing polarization-induced signal fading in an interferometric fiber optic sensor is disclosed. The apparatus includes an optical source for providing an input light beam, a polarization modulator for modulating the state of polarization of the input beam into at least three states represented by mutually perpendicular polarization vectors on a Poincare Sphere. The apparatus further includes means for conveying the input light beam with the at least three mutually perpendicular modulated states of polarization to the fiber optic sensor, the interferometric fiber optic sensor being responsive to the input light beam with modulated polarization states for developing an interference pattern output, wherein the interference pattern output has at least three visibilities corresponding to the input states of polarization. A photodetector is responsive to the interference pattern output for developing an electrical signal having at least three amplitudes corresponding to the at least three states of polarization. An output circuit is responsive to the electrical photodetector signal for time-sampling the photodetector signal having three amplitudes corresponding to the at least three mutually perpendicular input states of polarization and selecting the one having maximum visibility. A method for minimizing polarization-induced signal fading is also disclosed. Patent applications. (JHD)

Descriptors :   *CONTROL, *INTENSITY, *FIBER OPTICS, *LIGHT, *PATENT APPLICATIONS, *POLARIZATION, AMPLITUDE, OPTICAL DETECTORS, BEAM FORMING, INPUT, INTERFERENCE, INTERFEROMETRY, MODULATION, MODULATORS, OUTPUT, PATTERNS, PHOTODETECTORS, VISIBILITY, FADING(ELECTROMAGNETIC WAVES)

Subject Categories : Fiber Optics and Integrated Optics
      Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE