Abstract: A method for damping an optical fiber on a bias optical phase modulator having two optical fiber leads comprises the steps of securing the bias phase modulator, applying a silicone or acrylate type of substance to an outward facing surface of the fiber wound on the bias phase modulator means, applying the silicone or acrylate type of substance on the two optical fiber leads for at least 0.5 inch (1.28 cm.) along each lead which is apart from the place where the optical fiber wound on the bias phase modulator, frequently brushing or smoothing out the applied silicone or acrylate type of substance until the substance beings to set, and drying the substance on the optical fiber until the substance is cured. The applied damping material significantly reduces an amplitude of a frequency caused by mechanical vibrations in a rotation sensor.

Abstract: A rotation sensor for sensing rotation, particularly about an axis of a coiled optical fiber, wherein the coiled optical fiber has with light waves propagating in opposite directions in the coiled optical fiber, the phase relationship of the counter-propagating light waves providing a basis for indicating rotation of the sensor. A portion of the coiled optical fiber is a part of and affected by a bias optical phase modulator which causes a varying phase relationship between the light waves at a fundamental frequency. However, the varying phase relation ship has at least one harmonic which is due to mechanical vibration of the optical fiber that is a part of the modulator. This harmonic contributes to an erroneous indication of rotation. The amplitude of such harmonic is reduced by lowering the Q of the resonating fiber. This is effected by applying a damping material to the optical fiber and a portion of the modulator.

Abstract: An error control arrangement for an optical fiber rotation sensor having electromagnetic waves propagating in opposite directions passing through a bias optical phase modulator operated by a phase modulation generator both of which can contribute second harmonic distortion resulting in errors in the sensor output signal which are controlled. Control of the bias optical phase modulator contribution for a modulator having a piezoelectric body wrapped with an optical fiber portion is accomplished by mounting the body utilizing layers having nonlinear stiffness.