Encoded Probing Technique for Detection of the Faulty Branch in TDM-PON

We propose a method to precisely detect the faulty branch of time-division-multiplexing-passive optical networks (TDM-PONs) by encoding the probe signal with optical orthogonal codes. The proposed technique projects each probe signal response onto an orthogonal space, wherein an event corresponding to each branch of the TDM-PON is uniquely mapped onto an orthogonal basis and thereby able to isolate the origin of the event to a particular branch. A proof-of-concept experiment is carried out on a 1 × 16 TDM-PON with 20 km feeder fiber and the results confirm that, with the proposed design the system can support up to 120 m branch fiber length with 3 m spatial resolution.