Viability of in-service, low-cost and spatially unambiguous OTDR monitoring in TDM- and WDM-PON access networks

Abstract

A new strategy is proposed to efficiently monitor fibre plant failures in current and future optical access networks by implementing an OTDR subsystem in the physical layer. The viability of the method is evaluated by analyzing its theoretical performance limits. Experimental results demonstrate the applicability of the method.

Feasibility of Centralized Passive Optical Network Monitoring Using Passive Optical Network-Tuned Optical Time-Domain Reflectometry

“…Combining Eqs. (3), (9), and (10) and proceeding similarly as in Eq. (5), in order to take into account the losses and non-uniformity effects, the following is obtained after some calculations: …”

“…In fact, some manufacturers have already developed "PON reflectors," which act as mirrors at the 1,625-nm wavelength and are otherwise transparent to all other relevant wavelengths [26]. The literature also has many examples of how end reflectors can improve PON supervision [9][10][11][12]. On the other hand, from the network operator's point of view, it is rather unfeasible to install additional hardware features close to or within optical network terminations (ONTs), as those are the most cost-sensitive network elements.…”

“…Fiber identification ("labeling"), on the other hand, is not possible without recurring to fault location techniques, which may include additional components in the network. Many coding schemes using the end-fiber reflections have been proposed [9][10][11][12], as well as higher-level identification procedures, e.g., using layer-2 supervision capabilities. Nevertheless, it is still possible to calculate the loss value from the OTDR trace, assuming that there are no faults in different fibers at the exact same distance from the splitter (within the measurement resolution).…”

Cable television monitoring system based on fiber laser and FBG sensor

“…They can provide more channels than analog wireless television systems, and satisfy the demand for high video quality. When such the optical fiber cable television systems have been installed, a real-time optical link monitoring system is important [5][6][7][8][9][10][11][12]. Monitoring should be performed without affecting the delivery of the services to the subscribers.…”

Novel Monitoring Technique for Passive Optical Networks Based on Optical Frequency Domain Reflectometry and Fiber Bragg Gratings

“…In today's PON networks the physical infrastructure is usually not entirely visible to the network management system. A physical layer monitoring strategy should therefore be viable and easily integrated into the network management system [1,2].…”