Abstract: A sensing coil is provided for optically guiding counter-propagating light beams in a fiber optic gyroscope. The sensing coil comprises a plurality of layers of an optical fiber having a winding direction. The plurality of layers comprises inner layers, middle layers, and outer layers. The middle layers comprise first and second input ends configured to receive the counter-propagating light beams. At least one of the inner layers, middle layers, and outer layers is coupled with a different one of the inner layers, middle layers, and outer layers while maintaining the winding direction. A method is provided for winding an optical fiber, having first and second connecting ends, to form a sensing coil for a fiber optic gyroscope having a winding direction.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope-operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form, which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A pumped rare-earth fiber source wavelength control device, having source wavelength control effected by pump source wavelength and power control. The maintaining of pump wavelength and power control can be attained several ways such as by use of a wavelength sensitive coupler, a short length of fiber having an embedded grating, and a modulated grating embedded fiber.

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: A spectrum stabilizer for stabilizing the wavelength of light emitted by a source for use in an optical system where the source can have that wavelength altered by varying one or more source parameters, such as source current, temperature and/or alignment of the output end of the source with an optical fiber of the optical system, and wherein light from a selected point in the optical system is coupled to a double mode waveguide for wavelength sensing.

Abstract: An axis alignment detector for aligning axes of two birefringent components or fibers at forty-five degrees relative to each other. Polarized light is put into one axis of one of the two components or fibers to be aligned. The light goes from the one fiber through a junction where the two components or fibers are to be aligned at forty-five degrees, into the axes of the other component or fiber. The other component or fiber is temporarily connected to a third birefringent component or fiber wherein light moves on into the third component or fiber. The light from the third component or fiber goes on through a polarizer on to a mirror or integrated optic interferometer. The interferometer provides an interference output that reveals when the two components or fibers have a forty-five degree axis alignment. Also, the interferometer output may be used to measure other angles of axis alignment.

Abstract: An optical source emits a source optical signal having a source optical signal power and a wavelength. A splitter or other similar device splits the source optical signal into a first optical signal having a first optical signal power and into a second optical signal having a second optical signal power such that the source optical signal power is split between the first optical signal power and the second optical signal power. This split is dependent upon the wavelength of the source optical signal. A first detector detects the first optical signal power and a second detector detects the second optical signal power. A controller responds to the first and second detectors in order to control the wavelength of the source optical signal.