Patent ID: 6208590
Filing Date: 2001-03-27
Classification: G01D

Abstract:
A Sagnac interferometric sensor array for acoustic sensing, said sensor array comprising:means for generating light pulses;an input/output directional coupler that separates the light pulses into a first and a second directions that point oppositely and direct to travel in a loop optical path, said separated light pulses recombining at said input/output directional coupler to interfere with each other after completing said loop;first N sub-delay lines disposed in series on a portion of said loop, each of said first N sub-delay lines giving a first predetermined delay time to said light pulses;second N sub-delay lines disposed in series on the other portion of said loop, each of said second N sub-delay lines giving a second predetermined delay time to said light pulses;first directional couplers, each located at the front end of each first sub-delay line in order to split light pulses traveling along said first sub-delay lines;second directional couplers, each located at the front end of each second sub-delay line in order to split light pulses traveling along said second sub-delay lines;a plurality of means for optical path connection, each linking corresponding ones of said first and second directional couplers, and forming a unit loop optical path including one first sub-delay line and one second sub-delay line therein; anda plurality of sensor heads, each disposed at the optical path linking the corresponding front/back ends of said first and second sub-delay lines,where N is an integer greater than one.