Patent ID: 6522797
Filing Date: 2003-02-18
Classification: G01H,G01V

Abstract:
An optical sensor system for seismic exploration comprising:at least one single mode optical fiber, mounted within a linear casing, the fiber having an input end and an opposite terminal end; a plurality of partially reflective intrinsic fiber mirrors incorporated into the fiber at predetermined, spaced intervals within the fiber, each pair of adjacent mirrors defining a long gauge, linear, acoustic sensor; a first optical coupler coupled to the input end of the fiber, the optical coupler having a first and a second output port; a pulsed laser optically coupled to the first output port of the optical coupler wherein the laser is adapted to provide an optical pulse width equal to or less than twice the one way time of travel of optical energy between the predetermined mirror intervals; a compensating interferometer optically coupled to the second output port of the first optical coupler for receiving optical energy reflected from the internal mirrors, the interferometer including a first path and a second path wherein the second path includes a time delay to the two way time of travel of optical energy between the predetermined mirror intervals; and a calibration system for calibrating the sensor system to substantially remove the effects of temperature and acceleration on the optical signal being received by the interferometer, the calibration system including a piezoelectric stretcher incorporated in the fiber, the stretcher having an input terminal for connection to a signal generator and an output terminal for connection to a signal receiver.