High intensity fabry-perot sensor

Abstract

In a Fabry-Perot interferometer based sensor if insufficient light reflected from the sensor re-enters the fiber, the results from the Fabry-Perot interferometer-based sensor are compromised. Accordingly, a sensor assembly is provided that comprises an optical fiber having an optical axis, a lens in optical communication with the optical fiber, the lens having an optical axis and the lens capable of transmitting a beam of light, a reflective surface, the reflective surface spaced from the lens such that the beam of light transmitted from the lens is capable of reflecting from the reflective surface back to the lens, and an alignment device capable of aligning the beam of light transmitted from the lens substantially perpendicular with the reflective surface.

1 . A sensor assembly comprising: 
 an optical fiber having an optical axis;    a lens in optical communication with said optical fiber, said lens having an optical axis and said lens capable of transmitting a beam of light;    a reflective surface, said reflective surface spaced from said lens such that said beam of light transmitted from said lens is capable of reflecting from said reflective surface back to said lens; and    an alignment device capable of aligning said beam of light transmitted from said lens substantially perpendicular with said reflective surface.    
     
     
         2 . The sensor assembly of  claim 1 , further comprising a transparent window with a partially reflective surface, wherein said partially reflective surface of said window is substantially parallel with and is separated by a gap from said reflective surface, said optically transparent window and said reflective surface forming a Fabry-Perot sensor.  
     
     
         3 . The sensor assembly of  claim 2 , wherein said lens comprises at least one of: a ball lens; a graded index lens; a lens that focuses light; and a lens that collimates lights.  
     
     
         4 . The sensor assembly of  claim 3 , further comprising a ferrule encasing said optical fiber, said ferrule aligning said optical axis of said optical fiber with said optical axis of said lens.  
     
     
         5 . The sensor assembly of  claim 3 , wherein said ball lens is attached to said optical fiber to align said optical axis of said optical fiber with said optical axis of said lens.  
     
     
         6 . The sensor assembly of  claim 5 , wherein said ball lens is attached to said optical fiber by melting or bonding said ball lens to said optical fiber.  
     
     
         7 . The sensor assembly of  claim 4 , wherein said ball lens is not attached to said optical fiber.  
     
     
         8 . The sensor assembly of  claim 1 , wherein said alignment device comprises: 
 a body having a socket aperture;    a ball rotatably positioned in said socket aperture;    wherein at least a portion of said optical fiber is positioned within said ball.    
     
     
         9 . The sensor assembly of  claim 8 , wherein said ball is rotatable to align said beam of light transmitted from said lens substantially perpendicular with said reflective surface.  
     
     
         10 . The sensor assembly of  claim 1 , wherein said alignment device comprises a wedge shaped window located between said lens and said reflective surface.  
     
     
         11 . The sensor assembly of  claim 1 , wherein said alignment device comprises a wedge shaped spacer located between said lens and said reflective surface.  
     
     
         12 . The sensor assembly of  claim 1 , wherein said alignment device comprises a transducer body having an axis and an end surface, said end surface machined at an angle relative to said transducer body axis to align said beam of light transmitted from said lens substantially perpendicular with said reflective surface.  
     
     
         13 . The sensor assembly of  claim 1 , wherein said reflective surface is a diaphragm.  
     
     
         14 . The sensor assembly of  claim 13 , wherein said diaphragm comprises at least one of: a flat diaphragm; a mesa diaphragm; a plug diaphragm; and a bellows diaphragm.  
     
     
         15 . The sensor assembly of  claim 13 , wherein said diaphragm has a dielectric reflective surface.  
     
     
         16 . The sensor assembly of  claim 15 , wherein said diaphragm comprises a mesa diaphragm, said mesa diaphragm comprising a circular groove substantially surrounding said dielectric reflective surface.  
     
     
         17 . The sensor assembly of  claim 13 , wherein said diaphragm has a flat or a concave reflective surface.  
     
     
         18 . The sensor assembly of  claim 1 , further comprising a flexible tube encasing at least a portion of said optical fiber to form a flexible transducer.  
     
     
         19 . A Fabry-Perot sensor assembly comprising: 
 an optical fiber;    a ball lens in optical communication with said optical fiber said ball lens capable of transmitting a beam of light;    a window having a first surface and a second surface;    a diaphragm spaced from and parallel to said second surface of said window, said diaphragm having a partially reflective surface; and    an alignment device capable of aligning said beam of light transmitted from said ball lens substantially perpendicular with said partially reflective dielectric coating of said diaphragm.    
     
     
         20 . The Fabry-Perot sensor assembly of  claim 19 , wherein said ball lens is attached to said optical fiber.  
     
     
         21 . The Fabry-Perot sensor assembly of  claim 20 , wherein attaching said ball lens to said fiber is accomplished by melting an end of said fiber in a controlled manner.  
     
     
         22 . The Fabry-Perot sensor assembly of  claim 21 , wherein said alignment device comprises at least one of: a ball and socket arrangement; a wedged shaped window; a wedge shaped spacer; and an angled transducer body.  
     
     
         23 . The Fabry-Perot sensor assembly of  claim 19 , further comprising a flexible tube encasing at least a portion of said optical fiber to form a flexible transducer.  
     
     
         24 . A sensor assembly comprising: 
 a body having a socket;    a ball rotatably positioned in said socket of said body;    an optical fiber, at least a portion of said optical fiber positioned in said ball;    a ball lens attached to said optical fiber, said ball lens capable of transmitting a beam of light;    a diaphragm having a reflective surface, said diaphragm spaced from said ball lens such that said beam of light transmitted by said ball lens is capable of reflecting from said surface of said diaphragm back to said ball lens; and    wherein rotation of said ball aligns said beam of light transmitted from said ball lens substantially perpendicular with said reflective surface of said mesa diaphragm.