Aligned embossed diaphragm based fiber optic sensor

Abstract

The present invention is a diaphragm-fiber optic sensor (DFOS), interferometric sensor. This DFOS is based on the principles of Fabry-Perot and Michelson/Mach-Zehnder. The sensor is low cost and is designed with high efficiency, reliability, and Q-point stability, fabricated using MEMS (micro mechanic-electrical system) technology, and has demonstrated excellent performance. A DFOS according to the invention includes a cavity between two surfaces: a diaphragm made of silicon or other material with a rigid body (or boss) at the center and clamped along its edge, and the endface of a single mode optic fiber. By utilizing MEMS technology, the gap width between the diaphragm and the fiber endface is made accurately, ranging from 1 micron to 10 microns. To stabilize the Q-point of the DFOS when in use as an acoustic sensor, a system of microchannels is built in the structure of the diaphragm so that the pressure difference on two sides of the diaphragm is kept a constant, independent of the hydraulic pressure and/or low frequency noise when the device is inserted in liquid mediums.

1 . An embossed diaphragm-based fiber optic sensor.  
   
   
       2 . The sensor of  claim 1 , wherein the sensor is fabricated using micro mechanic-electrical system technology.  
   
   
       3 . The sensor of  claim 2  further comprising a diaphragm.  
   
   
       4 . The sensor of  claim 3  further comprising a single mode optic fiber and a cavity between the diaphragm and an endface of the single mode optic fiber.  
   
   
       5 . The sensor of  claim 3 , wherein the diaphragm is mechanically clamped.  
   
   
       6 . The sensor of  claim 1  further comprising at least one microchannel.  
   
   
       7 . The sensor of  claim 1 , wherein the sensor is Q-point stabilized.  
   
   
       8 . A fiber optic sensor comprising: 
 a vibrating diaphragm;    a single mode optic fiber having an endface; and    a Fabry-Perot type cavity between the diaphragm and the endface.    
   
   
       9 . The sensor of  claim 8 , wherein the sensor is fabricated using micro mechanic-electrical system technology.  
   
   
       10 . The sensor of  claim 8 , wherein the diaphragm is mechanically clamped.  
   
   
       11 . The sensor of  claim 8  further comprising at least one microchannel.  
   
   
       12 . The sensor of  claim 8 , wherein the diaphragm is embossed.  
   
   
       13 . The sensor of  claim 8 , wherein the sensor is Q-point stabilized.  
   
   
       14 . The sensor of  claim 8 , wherein the sensor is adapted for acoustic sensing in liquid mediums.  
   
   
       15 . The sensor of  claim 8 , wherein the sensor is adapted for at least one of optical, mechanical, pressure, temperature, chemical, biometric and acoustic sensing.  
   
   
       16 . The sensor of  claim 8 , wherein the sensor is adapted for detecting an on-line acoustic signature of sparking and arcing in a multitude of applications including at least one of large electric utility transformers, auto-transformers, tap-changers, phase angle regulators, voltage regulators, reactors, circuit breakers, pipe-type high voltage cables, and, other oil insulated utility and electric equipment.  
   
   
       17 . A method of fabricating a diaphragm-based fiber optic sensor, the method comprising: 
 forming a cavity between a diaphragm and the endface of a single mode optic fiber; and    embossing the diaphragm.    
   
   
       18 . The method of  claim 17  further comprising mechanically clamping the diaphragm.  
   
   
       19 . The method of  claim 17  further comprising forming microchannels in the diaphragm using micro mechanic-electrical system technology.  
   
   
       20 . The method of  claim 17  further comprising stabilizing the Q-point of the optic sensor.  
   
   
       21 . The method of  claim 17  further comprising detecting on-line acoustic signature of sparking and arcing in at least one of large electric utility transformers, auto-transformers, tap-changers, phase angle regulators, voltage regulators, reactors, circuit breakers, and pipe-type high voltage cables.