Patent ID: 8509613
Filing Date: 2013-08-13
Classification: H04B

Abstract:
1. A method for measuring a distribution of reflectivity along a fiber-optic transmission link connected to an optical transmitter, the method comprising the steps of: (a-1) filtering a data signal transmitted by the optical transmitter by using a low-pass filter; (a-2) detecting a back-reflected optical signal that returns to the optical transmitter and converting it to an electrical signal; (a-3) filtering the detected back-reflected optical signal by using a low-pass filter; (a-4) calculating a cross-correlation function, q(τ), between the filtered data signal and the filtered back-reflected optical signal, wherein τ is time and the cross-correlation function q(τ) is obtained by ensemble average of the filtered data signal and the filtered back-reflected optical signal; and (a-5) converting time axis of the calculated cross-correlation function q(τ) from time τ to distance z from the optical transmitter and obtaining the distribution of the reflectivity as R(z)=k·q(2z/ν