INTERFEROMETER GYRO USING HETERODYNE PHASE DETECTION WITHOUT SEVERE LIGHT SOURCE COHERENCE REQUIREMENTS

摘要

INTERFEROMETER GYRO USING HETERODYNE PHASE DETECTIONWITHOUT SEVERE LIGHT SOURCE COHERENCE REQUIREMENTSABSTRACT OF THE DISCLOSUREAn interferometer gyro employing a coiled optical fiber includesa pair of acousto-optic modulators to modulate first and secondfrequencies onto two components divided from the light of a lightsource. The light source need not exhibit the high degree of sourcecoherence heretofore required, and can be an incandescent bulb in many :applications. The first and second modulated light components æ einjected in opposite or counter-rotating directions into the opticalfiber wherein they experience phase changes due to the apparent changein optical length of the optical fiber upon rotation of the fiber aboutan axis of sensitivity. The light components are then, after beingremoved from the fiber, combined and compared with the signals appliedat the input. The phase difference therebetween is then established tomeasure the rate of rotation of the optical fiber about the axis ofsensitivity.-1-