Optical multiple-input multiple-output (MIMO) technology is introduced into optical space division multiplexing (SDM) communication as an effective solution for the crosstalk issue. Unfortunately, this application is limited because all the channel information over the transmission link must be transmitted to MIMO receivers for complete crosstalk compensation, which indicates difficulty in applying MIMO to the transmission path via optical switches. We newly propose that one of the solutions to this limitation is a ring network because all channel information can be maintained in the ring. In particular, a typical ring network model comprising optical add-drop multiplexers (OADMs) and multicore fibers (MCFs) is introduced, and the ability of MIMO to compensate for capacity degradation because of the inter-core crosstalk is investigated. Moreover, the protection function, which is essential for the ring network, is also evaluated under the fiber and fiber core failures. As per the simulation results, although the protection operation affects the transmission capacity, the capacity loss is suppressed in the event of a failure to < 5%. We believe that these results provide useful information for designing SDM-based optical networks.

光多输入多输出 (MIMO) 技术被引入到光空分复用 (SDM) 通信中，作为串扰问题的有效解决方案。不幸的是，这种应用是有限的，因为传输链路上的所有信道信息都必须传输到 MIMO 接收器以进行完整的串扰补偿，这表明通过光开关将 MIMO 应用于传输路径很困难。我们新提出解决此限制的方法之一是环网，因为所有信道信息都可以在环中维护。特别地，介绍了包括光分插复用器 (OADM) 和多芯光纤 (MCF) 的典型环形网络模型，并研究了 MIMO 补偿由于芯间串扰导致的容量下降的能力。而且，环网必不可少的保护功能也在光纤和纤芯故障下进行评估。根据仿真结果，虽然保护动作影响输电容量，但故障时容量损失被抑制在<5%。我们相信这些结果为设计基于 SDM 的光网络提供了有用的信息。