Patent ID: 8670662
Filing Date: 2014-03-11
Classification: G01D

Abstract:
1. A method of interferometrically evaluating the position of a time varying disturbance on an optical waveguide, comprising: transmitting a plurality of outbound sensing signals from a continuous wave incoherent optical source onto the optical waveguide, which outbound sensing signals have imposed thereon a modulation by a modulation signal having a frequency which is dependent, at least in part, on the time of transmission of the outbound sensing signals, wherein the outbound sensing signals are guided along an outbound path along the optical waveguide; receiving disturbance sensing signals, which are progressively returned from the outbound path by a process of distributed backscattering, wherein the disturbance sensing signals have been exposed to the disturbance, wherein the disturbance sensing signals are returned in a reverse direction along a waveguide portion of the optical waveguide, the waveguide portion comprising the same waveguide portion used to guide the outbound sensing signals in the outbound direction; and using the previously imposed outbound modulation on the sensing signals, evaluating the position of the disturbance from the progressively returned disturbance sensing signals.