This work presents a novel delta-star architecture for large-scale multipoint fiber sensor networks with enhanced reconfigurable functionality. Unlike conventional star networks, the proposed network is divided into several delta regions, each containing only one feeder fiber. This delta-star structure significantly reduces the complexity and implementation cost of conventional star networks. A concatenated dual-ring structure with the self-healing function is designed to overcome the star's weakness in reliability. Numerous sensor ring subnets (SRSNs) are utilized to serve a large number of fiber Bragg grating sensors. Delta regions are partitioned upon the criterion of inter-region traffic uniformization; this simplifies the interrogation process and time slot assignment. The reconfigurable function for this multipoint sensor network, which is based on the optical switching technique, is utilized to ensure service continuity when fibers fail. The protection mechanism is illustrated with several multiple link failure cases. Finally, an experimental network is implemented to demonstrate the feasibility and survivability of the proposed sensor network.Index Terms-Delta-star network, fiber Bragg grating (FBG), fiber ring laser, fiber sensor network, network partitioning, reconfigurable function.

This letter presents a reliable hexagonal mesh architecture for a large-area multipoint fiber sensor system. While covering a large area, the proposed mesh architecture demarcates a large number of fiber sensing regions. Within each sensing region, a ring subnet is constructed to serve many fiber Bragg grating (FBG). In particular, the proposed sensor system incorporates the fiber laser scheme cooperation with the signalaveraging module to enhance its signal-to-noise ratio (SNR) performance. The self-restored capability of the proposed system is achieved by optical switches, allowing it to protect numerous FBG sensors against fiber break(s). A higher SNR with respect to any FBG sensor setting in our experiment is available due to the signal-averaging module.Index Terms-Signal-averaging module, mesh architecture, fiber sensor system.

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In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.