Abstract: A measuring arrangement for fiber Bragg grating measurement points and particularly a measuring arrangement for two fiber Bragg gratings (FBG), wherein a first measurement point is subjected to tension and a second measurement point is subjected to pressure, or vice versa. The circuit arrangement includes a broadband light source, a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, photodiodes and an optical delay element.

Abstract: A measuring arrangement for fiber Bragg grating measurement points and particularly a measuring arrangement for two fiber Bragg gratings (FBG), wherein a first measurement point is subjected to tension and a second measurement point is subjected to pressure, or vice versa. The circuit arrangement includes a broadband light source, a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, photodiodes and an optical delay element.

Abstract: A sensing apparatus (20) based on fiber optics including fiber gratings for monitoring stator slot temperatures in an electromotive machine (10) is provided. The apparatus may include a dielectric strip (22) to be received in a gap between a first stator bar (16) and a second stator bar (18) in a stator slot (14). One or more optical fibers (24, 25) may be disposed in the dielectric strip and extend along a longitudinal axis of the dielectric strip. A plurality of sites 28 in the optical fiber include a respective fiber Bragg grating arranged to have a respective optical response in a wavelength spectrum indicative of a value of temperature at the grating site.

Abstract: A sensing apparatus (20) based on fiber optics including fiber gratings for monitoring stator slot temperatures in an electromotive machine (10) is provided The apparatus may include a dielectric strip (22) to be received in a gap between a first stator bar (16) and a second stator bar (18) in a stator slot (14) One or more optical fibers (24, 25) may be disposed in the dielectric strip and extend along a longitudinal axis of the dielectric strip A plurality of sites 28 in the optical fiber include a respective fiber Bragg grating arranged to have a respective optical response in a wavelength spectrum indicative of a value of temperature at the grating site

Abstract: A sensor includes a housing adapted to be secured to a component within a system to be monitored by the sensor, an optical fiber, and a membrane spring assembly. The optical fiber includes a sensing portion containing a fiber Bragg grating that is able to undergo expansion and contraction resulting from movement of the optical fiber at a second location relative to a first location. The membrane spring assembly includes a membrane disc, wherein movement of a central portion thereof causes corresponding displacement of the optical fiber at the second location to cause expansion and contraction of the sensing portion of the optical fiber containing the fiber Bragg grating, which expansion and contraction effects a change in a light wavelength reflected by the fiber Bragg grating. The light wavelength reflected by the fiber Bragg grating can be used to measure movement of the central portion of the membrane disc.

Abstract: A sensor includes a housing adapted to be secured to a component within a system to be monitored by the sensor, an optical fiber, and a membrane spring assembly. The optical fiber includes a sensing portion containing a fiber Bragg grating that is able to undergo expansion and contraction resulting from movement of the optical fiber at a second location relative to a first location. The membrane spring assembly includes a membrane disc, wherein movement of a central portion thereof causes corresponding displacement of the optical fiber at the second location to cause expansion and contraction of the sensing portion of the optical fiber containing the fiber Bragg grating, which expansion and contraction effects a change in a light wavelength reflected by the fiber Bragg grating. The light wavelength reflected by the fiber Bragg grating can be used to measure movement of the central portion of the membrane disc.

Abstract: Fiber Bragg gratings (FBGs) are particular suitable for measuring strain. However, a single parameter measurement is difficult to implement, since cross-sensitivity to temperature compels the use of an additional temperature reference, e.g. a strain-inactive FBG. The development of a passive athermal fiber Bragg grating strain gage is thus of particular interest since it renders optional the measurement of temperature, benefiting large scale system design and performance. In view of this need, a package for fiber Bragg gratings that enables strain measurements to be performed while canceling temperature sensitivity is disclosed. The proposed design is based on a structure composed of two parts, which can be made of the same material, having a defined length ratio that allows the adjustment of the temperature sensitivity to zero, providing athermal operation of the strain gage.