Abstract: A system for interrogating sensors in a fiber optical sensor network includes groups of sensors. The sensors in one group operate at different wavelengths, and the sensors of other groups may have overlapping wavelengths. A light source generates a broadband light signal, input and output means for guides the broadband light to the fiber optical sensor network for illuminating the sensors and for coupling the light signal coming from the sensors of the fiber optical sensor network to the detection system, and a detection system detects the received light signal, during a detection integration time. The system is arranged for selecting pre-dominantly the received light coming from the different sensors of a selected group of sensors using a code-division multiplexing technique and simultaneously detecting sensors of the selected group of sensors using a wavelength-division multiplexing technique.

Abstract: A system for interrogating sensors in a fiber optical sensor network includes groups of sensors. The sensors in one group operate at different wavelengths, and the sensors of other groups may have overlapping wavelengths. A light source generates a broadband light signal, input and output means for guides the broadband light to the fiber optical sensor network for illuminating the sensors and for coupling the light signal coming from the sensors of the fiber optical sensor network to the detection system, and a detection system detects the received light signal, during a detection integration time. The system is arranged for selecting pre-dominantly the received light coming from the different sensors of a selected group of sensors using a code-division multiplexing technique and simultaneously detecting sensors of the selected group of sensors wavelength-division multiplexing technique.

Abstract: A sensor (1) has a light conductor (2) having a grating (FBG), a cavity (5), and a transparent cavity end wall (4), a light emitter for directing light through the conductor, and a light detector for detecting reflected light, and a processor. The processor is adapted to analyse light reflected due to the grating (FBG, 6) to determine an indication of temperature, light reflected from the end (7) of the cavity (5) to determine an indication of pressure, and also light reflected from the outer surface (8) of the cavity wall (4) to determine an indication of refractive index of a medium outside said cavity wall. The processor may use one output to compensate another, for example pressure and temperature may be used to compensate for variation in refractive index.

Abstract: A pressure sensor (10 for medical applications comprises a silica optical fiber extrinsic Fabry-Perot interferometric (EFPI) pressure sensor (2) and an in-fiber Bragg grating (FBG, 3). The cavity of the EFPI pressure sensor (2) is formed by the end face of the FBG (3), a glass capillary (5) and a glass diaphragm (6). The glass diaphragm (6) is secured in place by a fusion splice (7) and the glass capillary (5) by a fusion splice (8). As illustrated, incident light is directed into the FBG 3 and there are reflections in the EFPI pressure sensor (2). Applied pressure causes a deflection of the glass diaphragm (6) and hence modulation of the EFPI sensor (2) cavity. The FBG (3) is used as a reference sensor to eliminate temperature cross-sensitivity of the EFPI pressure sensor (2). The EFPI cavity was fabricated using a 200 ?m silica glass fiber, a 133/220 ?m (inner/outer diameter) silica glass capillary and a standard telecommunication FBG.

Abstract: A pressure sensor (10 for medical applications comprises a silica optical fiber extrinsic Fabry-Perot interferometric (EFPI) pressure sensor (2) and an in-fiber Bragg grating (FBG, 3). The cavity of the EFPI pressure sensor (2) is formed by the end face of the FBG (3), a glass capillary (5) and a glass diaphragm (6). The glass diaphragm (6) is secured in place by a fusion splice (7) and the glass capillary (5) by a fusion splice (8). As illustrated, incident light is directed into the FBG 3 and there are reflections in the EFPI pressure sensor (2). Applied pressure causes a deflection of the glass diaphragm (6) and hence modulation of the EFPI sensor (2) cavity. The FBG (3) is used as a reference sensor to eliminate temperature cross-sensitivity of the EFPI pressure sensor (2). The EFPI cavity was fabricated using a 200 ?m silica glass fiber, a 133/220 ?m (inner/outer diameter) silica glass capillary and a standard telecommunication FBG.