Patent ID: 7471895
Filing Date: 2008-12-30
Classification: H04B

Abstract:
1. A method of locating a fault arising in one or more optical amplifiers from among a plurality of optical amplifiers operating in saturation and located along an optical transmission path, said method comprising the step of: generating a coherent optical time domain reflectometry (COTDR) trace representing a backscattered and/or reflected optical power level along the transmission path; comparing the COTDR trace to a previously obtained reference COTDR trace to generate a difference trace; and assigning the difference trace to a fault in at least one of the plurality of optical amplifiers based on the difference trace wherein the assigning step comprises the step of assigning the difference trace to faults in a plurality of the optical amplifiers, and further comprising the steps of: equating the difference trace with a linear combination of difference trace vectors each arising from a fault in a different one of the optical amplifiers; and iterating to determine a value for a coefficient associated with each of the difference trace vectors, wherein each of the coefficients having a nonzero value denotes a fault in an optical amplifier corresponding to the difference trace vector with which the coefficient is associated.