Resilient single-star and passive double-star fiber links for point-to-multipoint optical networks with switchable path protection

This study focuses on the design of a new, to the best of our knowledge, switchable network with disaster resilience in mind. Specifically, it introduces a redundant link configuration consisting of a single star (SS) type provided to each optical distribution terminal (ODT) as the primary link and a passive double star (PDS) type provided to all ODTs as the secondary link. This configuration allows for a point-to-multipoint (P-to-MP) optical network that can switch between SS and PDS links using an optical switch to achieve rapid recovery and improved reliability during disasters. The study meticulously compares the capital cost and availability of the SS configuration, the PDS configuration, and the SS/PDS switchable configuration with and without variable reflection blocking (VRB). In addition, a bidirectional transmission experiment was conducted using wavelength conversion with two light sources and VRB to address single-link failures. The experimental results unequivocally confirmed that the proposed configuration functions effectively during link failures, ensuring energy-efficient operation and superior capital cost efficiency. Furthermore, it was demonstrated that using VRB at the ODT side allows for bidirectional communication while effectively suppressing reflections, further enhancing the system’s capital and operation cost efficiency. The proposed P-to-MP optical network configuration effectively ensures redundancy and reliability while accommodating the expanded scale of optical fiber deployment in next-generation mobile communication systems.