Patent ID: 8805184

Claim:
A method for locating faults in a passive optical network (PON), comprising: providing a number of passive unique optical correlators at a number of respective diagnostic points of the PON, each of the passive unique optical correlators being configured to respond to a signal pattern representing a respective unique signature and being responsive to an optical diagnostic signal by returning a predetermined unique matching signal; transmitting the diagnostic optical signal in said PON towards said diagnostic points, wherein said diagnostic signal comprises a plurality of respectively different signal patterns each representing a respective unique signature, each characterizing a specific passive optical correlator and each optical correlator being characterized by a respective one of the unique signatures that is different from the unique signature characterizing any other one of said optical correlators, thereby enabling generation of a matching signal by the specific optical correlator in response to receiving by said specific passive optical correlator the diagnostic signal that comprises a respective signal pattern, receiving upstream response signals from one or more of said plurality of passive optical correlators which had received the diagnostic signal, detecting presence or absence, in said received response signals, of a predetermined unique matching signal expected from a specific optical correlator out of said optical correlators, and judging about a fault in proximity of a specific diagnostic point, based on the presence or absence and/or a level of said specific matching response signal expected from the optical correlator placed in said specific diagnostic point.