A new fault-identification method using Access Control System in PON appliance

A new method is studied which can automatically identify faults between an optical splitter and the multiple optical network unit (ONU) on the customer's side. This method employs an Access Control System (ACS) in the middle fiber plant, and inserted between the optical line terminal (OLT) and the ONU. The ACS is using OTDR basic source at 1625 nm wavelength from the central office (CO) in this fault identification method. The required characteristics and structural design method for the ACS are discussed. A prototype of the ACS is fabricated and which achieves the target characteristics and reliability. System evaluation experiments are carried out and the possibility of 100% fault identification is confirmed as a result of accuracy tests in the field.