Patent ID: 6317213
Filing Date: 2001-11-13
Classification: G01L

Abstract:
A system for sensing changes in the value of an environmental parameter, comprising:an optical signal source;an interferometer optically coupled to the light source so as to receive an optical signal therefrom, the interferometer comprising:means for splitting the optical signal into first and second beams;first and second optical fibers respectively providing first and second optical paths for the first and second beams, respectively, the optical path length through the second optical path being substantially longer than the optical path length through the first optical path, the second optical fiber having a distal end;a fixed mirror terminating the first optical path so as to reflect the first beam back into the first optical fiber;a sensor having a proof mass that is movable in response to a change in the value of the parameter;a reflective surface on the proof mass that forms a movable mirror spaced from the distal end of the second optical fiber and terminating the second optical path so as to reflect the second beam back into the distal end of the second optical fiber, the movable mirror being movable relative to the distal end of the second fiber in response to a change in the value of the parameter; andoptical coupling means for recombining the first and second beams after their reflection back along the respective optical fibers by the fixed and movable mirrors, respectively, so as to form an interference signal;optical detector means, responsive to the interference signals for generating an electrical signal indicative of the value of the interference signal; andmeans, responsive to the electrical signal, for correlating a change in the value of the interference signal with a change in the value of the parameter.