Abstract: The present invention relates to a diaphragm for a pressure sensor, the diaphragm comprising a hybrid sol-gel film. The invention also extends to a process for the manufacture of said diaphragm for a pressure sensor and to a pressure sensor comprising said diaphragm.

Abstract: A temperature sensor (1) has a pressure sensor (10), the distal end of which is inserted in a sealed chamber (2) filled with a liquid. The pressure sensor has a light guide (4), a cavity (14) at a distal end of the light guide, a diaphragm (11) forming a wall of the cavity and being configured to deflect with applied pressure, and a detector to detect changes in light reflection due to deflection of the diaphragm. The liquid (3) which changes volume in response to temperature changes and this volume change is sufficient to change the pressure applied on the diaphragm (11), and the a interrogation system processes pressure data and/or light reflection data to generate an output indicating temperature of the fluid in the chamber.

Abstract: A temperature sensor (1) has a pressure sensor (10), the distal end of which is inserted in a sealed chamber (2) filled with a liquid. The pressure sensor has a light guide (4), a cavity (14) at a distal end of the light guide, a diaphragm (11) forming a wall of the cavity and being configured to deflect with applied pressure, and a detector to detect changes in light reflection due to deflection of the diaphragm. The liquid (3) which changes volume in response to temperature changes and this volume change is sufficient to change the pressure applied on the diaphragm (11), and the a interrogation system processes pressure data and/or light reflection data to generate an output indicating temperature of the fluid in the chamber.

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.