Abstract: Systems and methods for calibrating a temperature sensing system are disclosed. In one respect, a dual light source configuration may be provided. A first light source may illuminate a sensing fiber and an anti-Stokes band may be detected. A second light source may illuminate a sensing fiber and a Stokes band may be detected, where the Stokes band is substantially similar to the anti-Stokes band of the first light source. A ratio between the anti-Stokes and Stokes band may be used to calibrate a temperature sensing system.

Abstract: Systems and methods for detecting corrosion are provided. In one embodiment, a luminescent material coupled to a cladding of an optical fiber may be altered when exposed to corrosion. The backscatter emission of the luminescent material, which includes the altered optical properties, may be used to determine properties of the corrosion including, for example, thickness, or location of the corrosion.

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: Apparatus and method (10, 50) for determining the value of a measurand measured by a fiber optic interferometer sensor (24, 72, 110) is provided. The apparatus includes a light source (16, 58, 102) emitting a light having a periodically modulated frequency which is injected into the interferometric sensor. A modulation cycle is initiated by the microcontroller's (12, 56, 116) generation of a trigger signal. A counter (42, 86) begins counting in response to the trigger signal. A first photodetector (20, 66) is coupled to the light source (16, 58, 102) and produces a first electrical signal proportional to the light. A second photodetector (36, 76, 114) is coupled to the fiber optic interferometer sensor (24, 72, 110) and produces a second electrical signal proportional to the light reflected by the sensor or passed through the sensor and affected by the measurand.

Abstract: Apparatus for sensing intrusion into a predefined perimeter comprises means for producing a coherent pulsed light, which is injected into an optical sensing fiber having a first predetermined length and positioned along the predefined perimeter. A backscattered light in response to receiving the coherent light pulses is produced and coupled into an optical receiving fiber. The backscattered light is detected by a photodetector and a signal indicative of the backscattered light is produced. An intrusion is detectable from the produced signal as indicated by a change in the backscattered light. To increase the sensitivity of the apparatus, a reference fiber and an interferometer may also be employed.