Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: A system for sensing downhole pressure in in a hydrocarbon well using a Fabry-Perot (F-P) sensor in series with a Fiber Bragg Grating and maintaining the back pressure on the sensor system with a surface sealing system and a surface pressure control system.

Abstract: A sensor assembly having an optical fiber, a lens in optical communication with the optical fiber, a reflective surface spaced from the lens, for reflecting light from the beam back to the lens, a partially reflective surface positioned between the reflective surface and the lens, the partially reflective surface for reflecting light from the beam back to the lens, and an alignment device for aligning the lens and reflective surface with respect to one another, such that light from the beam of light transmitted from the lens reflects from the reflective surface back to the lens. The alignment device can have a rotational component and a base component, where the rotational component rotates to align a beam of light transmitted from the lens. The rotational component can also cooperate with the base component to move axially with respect to the reflective surfaces to align the beam for optimum power.

Abstract: A sensor assembly having an optical fiber, a lens in optical communication with the optical fiber, a reflective surface spaced from the lens, for reflecting light from the beam back to the lens, a partially reflective surface positioned between the reflective surface and the lens, the partially reflective surface for reflecting light from the beam back to the lens, and an alignment device for aligning the lens and reflective surface with respect to one another, such that light from the beam of light transmitted from the lens reflects from the reflective surface back to the lens. The alignment device can have a rotational component and a base component, where the rotational component rotates to align a beam of light transmitted from the lens. The rotational component can also cooperate with the base component to move axially with respect to the reflective surfaces to align the beam for optimum power.

Abstract: A method and apparatus for detecting seismic vibrations using a series of MEMS units, with each MEMS unit including an interferometer is described. The interferometers on the MEMS units receive and modulate light from two differing wavelengths by way of a multiplexing scheme involving the use of Bragg gratings and light circulators, and an optoelectronic processor receives and processes the modulated light to discern vibrational movement of the system, which in turn allows for monitoring and calculation of a specified environmental parameter, such as seismic activity, temperature or pressure.

Abstract: A method and apparatus for detecting seismic vibrations using a series of MEMS units, with each MEMS unit including an interferometer is described. The interferometers on the MEMS units receive and modulate light from two differing wavelengths by way of a multiplexing scheme involving the use of Bragg gratings and light circulators, and an optoelectronic processor receives and processes the modulated light to discern vibrational movement of the system, which in turn allows for monitoring and calculation of a specified environmental parameter, such as seismic activity, temperature or pressure.

Abstract: A fiber optic fiber Fabry-Perot interferometer diaphragm sensor and method of measurement is provided. A fiber Fabry-Perot interferometer diaphragm sensor (12a, 12b, 12c) includes a base (54a, 54b, 54c) and a diaphragm (52a, 52b, 52c) with an optic fiber (30) coupled under tension between the base (54a, 54b, 54c) and the diaphragm (52a, 52b, 52c). A fiber Fabry-Perot interferometer element (40) is contained within the optic fiber (30) and operates to sense movement of the diaphragm (52a, 52b, 52c). In a particular embodiment, the diaphragm (52a) moves in response to a pressure (P) applied to the diaphragm (52a). In another embodiment, a proof mass (72) is coupled to the diaphragm (52b) such that the diaphragm (52b) moves in response to an acceleration (A). In yet another embodiment, a magnetic body (80) is coupled to the diaphragm (52c) such that the diaphragm (52c) moves in response to a magnetic field (M).

Abstract: A method and apparatus are provided for measuring pressure in a combustion chamber of an internal combustion engine is provided with a non-intrusive, metal-embedded fiber optic pressure sensor. A Fabry-Perot Interferometer is arranged in a terminated, single mode fiber to function as a pressure gauge. The fiber Fabry-Perot Interferometer (FFPI) is embedded in a metal part which is disposed in the cylinder head of the engine. The metal part and FFPI experience a longitudinal compression in response to the pressure in the chamber. In another aspect of the invention, a non-intrusive fiber containing the FFPI is embedded in a hole drilled or otherwise provided in the metal housing of a spark plug. The spark plug is threaded into the cylinder head of an internal combustion engine and is directly exposed to the combustion chamber pressure. Consequently, the spark plug housing and FFPI experience a longitudinal strain in response to the pressure in the chamber.

Abstract: A method and apparatus is provided for measuring pressure in a pressure containing vessel with a non-intrusive, metal-embedded fiber optic pressure sensor. The pressure containing vessel may, for example, be the combustion chamber of an internal combustion engine. A Fabry-Perot Interferometer is arranged in a terminated, single mode fiber to function as a strain gauge. The fiber Fabry-Perot Interferometer (FFPI) is embedded in a metal part which may be disposed in a wall of the pressure containing vessel. The metal part and FFPI experience a longitudinal strain in response to the pressure in the vessel. In another aspect of the invention, a non-intrusive fiber containing the FFPI may be embedded along the axis of a metal bolt. The bolt may be used to attach a part or structure, which is directly exposed to the pressure, to the wall of the vessel. Consequently, the bolt and FFPI experience a longitudinal strain in response to the pressure on the part or structure.

Abstract: Optical fibers are embedded in metal structures and components by using a pair of stress-relieving tubes at the air-metal interface of the optical fiber.