Patent ID: 6285475
Filing Date: 2001-09-04
Classification: H04B,H04J,H04Q

Abstract:
A method for detecting an optical fault in a communication network, wherein the communication network includes first and second sites connected by a first fiber link carrying a modulated optical data signal between the first and second sites, the second site further including an intermediate optical cross-connect switch for optically coupling the modulated optical data signal between said first fiber link to a second fiber link, comprising the steps of:coupling a portion of an optical signal from the first fiber link before the optical signal enters the optical cross-connect switch;detecting said optical signal portion coupled from said first fiber link and generating a first electrical signal representative of said detected optical signal portion;processing said first electrical signal to determine whether said detected optical signal portion represents the presence or absence of a portion of the modulated optical data signal traveling through the first fiber link; andindicating an optical fault condition when said processing step determines the modulated data output signal is not present.