Patent ID: 6097486
Filing Date: 2000-08-01
Classification: G01D

Abstract:
An acoustic sensor system comprising:a source of light;a coupler which receives said light from said source and which couples a first portion of said light to a first coupler port and which couples a second portion of said light to a second coupler port;an interferometric loop having a first end coupled to said first coupler port to receive said first portion of said light and having a second end coupled to said second coupler port to receive said second portion of said light, said interferometric loop propagating said first portion of said light in a first direction to said second coupler port, said interferometric loop propagating said second portion of said light in a second direction opposite said first direction to said first coupler port, said interferometric loop comprising:a delay portion of said interferometric loop, said delay portion having a first end proximate to said first end of said interferometric loop and having a second end, said delay portion providing a time delay for light passing through said delay portion from said first end of said delay portion to said second end of said delay portion and for light passing through said delay portion from said second end of said delay portion to said first end of said delay portion; andan array having a first end coupled to said second end of said delay portion and having a second end coupled to said second end of said loop, said array comprising:at least a first acoustic sensor and a second acoustic sensor coupled between said first end of said array and said second end of said array, said second acoustic sensor being disposed farther from said second end of said delay portion and farther from said second end of said loop than said first acoustic sensor to cause said second acoustic sensor to receive light after said first acoustic sensor, said first acoustic sensor and said second acoustic sensor being responsive to an impinging acoustic signal to modulate light passing therethrough in said first and second directions;andat least one detector which receives light returned to said coupler from said interferometric loop, said detector detecting light phase modulated by said first acoustic sensor at a first time and detecting light phase modulated by said second acoustic sensor at a second time after said first time, said detector generating a detector output signal.