Remote sensing in optical fiber networks.

摘要

The occurrence and location of a disturbance in the vicinity of a localized portion of an optical fiber are determined based on the recognition that such a disturbance changes the polarization condition of signals backscattered from the disturbed portion. Multiple consistently polarized optical pulses are applied to an input end of the fiber. Only signals of a particular polarization that are backscattered from the disturbed portion are abstracted from the input end. An output signal indicative of the disturbance is generated by processing these backscattered signals in accordance with synchronous detection techniques.