Abstract: In a preferred embodiment, the invention provides a fiber optic pressure sensor apparatus which includes a light source, a reflective sensor diaphragm movable in accordance with pressure in a medium and an optical fiber coupled to the light source for delivering a first wavefront of light to the reflective sensor diaphragm. The optical fiber has an endface which is separated from the reflective sensor diaphragm by a gap, the endface receiving a second wavefront of light reflected from the reflective sensor diaphragm. The first and second wavefronts constructively and destructively interfere to create a modulated optical signal. A spectrometer is coupled to the optical fiber for converting the optical signal into a series of digital values, and means for analyzing the digital values is provided for obtaining a measurement of the pressure in the medium. An optical coupler is preferably provided for coupling the light source, the optical fiber, and the spectrometer.

Abstract: Described are improved transmissive magneto-optical sensors that may be used to determine the magnitude and phase of a magnetic field surrounding a conductor, and when in contact with the conductor, the surface temperature of the conductor. The magneto-optical sensor may be made to be symmetric around the direction of propagation of the internal light, enabling ease of manufacturing as well as automated assembly and calibration. The magneto-optical sensor may also be made to be symmetric about the plane determined by the Faraday rotator material, thus enabling reciprocating optical paths for increased vibration and birefringence immunity. The disclosed sensors preferably include cylindrically symmetrical components, thereby making the sensor readily mass-producible.

Abstract: Described are improved transmissive magneto-optical sensors that may be used to determine the magnitude and phase of a magnetic field surrounding a conductor, and when in contact with the conductor, the surface temperature of the conductor. The magneto-optical sensor may be made to be symmetric around the direction of propagation of the internal light, enabling ease of manufacturing as well as automated assembly and calibration. The magneto-optical sensor may also be made to be symmetric about the plane determined by the Faraday rotator material, thus enabling reciprocating optical paths for increased vibration and birefringence immunity. The disclosed sensors preferably include cylindrically symmetrical components, thereby making the sensor readily mass-producible.

Abstract: In a preferred embodiment, the invention provides a fiber optic pressure sensor apparatus which includes a light source, a reflective sensor diaphragm movable in accordance with pressure in a medium and an optical fiber coupled to the light source for delivering a first wavefront of light to the reflective sensor diaphragm. The optical fiber has an endface which is separated from the reflective sensor diaphragm by a gap, the endface receiving a second wavefront of light reflected from the reflective sensor diaphragm. The first and second wavefronts constructively and destructively interfere to create a modulated optical signal. A spectrometer is coupled to the optical fiber for converting the optical signal into a series of digital values, and means for analyzing the digital values is provided for obtaining a measurement of the pressure in the medium. An optical coupler is preferably provided for coupling the light source, the optical fiber, and the spectrometer.

Abstract: A method for calculating a distance from a fiber optic tip of a sensor to a reflective surface by high pass filtering a fringe signal gathered by a spectrometer, calculating a power spectral density of the filtered signal, and using a calibrated distance vs. peak spectral density wavelength curve to determine the measured distance. This fiber optic distance measurement technique can be applied to a variety of sensor types, including, but not limited to, pressure, displacement, temperature, acoustic, pressure, load, and magnetic field sensors.