Experimental Evaluation of Recovery From Multiple Failures in Multicore Fiber-Based Optical Network

We experimentally investigate recovery from multiple link failures in a multicore fiber (MCF) link-based optical network (NW). The NW is composed of an input/output interface and a two-ring structure to achieve high-capacity and highly reliable NWs in access areas. Each node has a switch (SW) unit consisting of field-programmable gate array (FPGA)-based optical SW units. The SW unit is able to detect failures and implements a failure recovery scheme that monitors signals and secures a restoration path, even when there are multiple link failures. Signal transmission experiments demonstrated that the path could be recovered within a short time period (approximately 8 ms), even after multiple failures in the NW. Moreover, performing a second (consecutive) switching after no signal was detected in the first switching for complicated multiple failures in the NW also led to recovery within a short time period (approximately 25 ms). These times are sufficiently less than that required by recovery time standard for telecommunication NWs of the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T). The results indicate that the MCF link would be useful for increasing the reliability of NWs.