Cost-effective and monitoring-active technique for TDM-passive optical networks

• It uses the monitoring wavelength within the ITU-T U-band to implement PON in-service maintenance functions.
• It provides a reliable and cost-effective approach to determine the faulty fiber branch among of the different fiber branches in TDM-PON. Furthermore, it can support the number of customers up to 256.
• Combining with the OTDR can exactly determine the location of the fault. The OTDR is only placed in the CO instead of in the customer side, hence reduces the restoration time and the maintenance cost.

A reliable, detection-active and cost-effective method which employs the hello and heartbeat signals for branched node distinguishing to monitor fiber fault in any branch of distribution fibers of a time division multiplexing passive optical network (TDM-PON) is proposed. With this method, the material cost of building an optical network monitor system for a TDM-PON with 168 ONUs and the time of identifying a multiple branch faults is significantly reduced in a TDM-PON system of any scale. A fault location in a 1 × 32 TDM-PON system using this method to identify the fault branch is demonstrated.