In this work, we first propose and demonstrate a bidirectional time-division-multiplexing (TDM) free space optical communication (FSO) traffic integrated in ring-based fiber access network together with fiber fault protection. Here, while we add the new designed optical devices in the central office (CO) and each optical wireless unit (OWU) respectively, the TDM-FSO fiber system can achieve the self-protected operation against fault. In addition, according to the proposed ring-based fiber network, the maximum numbers of eight OWUs can be provided for the symmetric 10 Gbps on-off keying (OOK) FSO downstream and upstream connections. As a result, the proposed FSO access network can allow 25 km fiber transmission and proper FSO transmission length depending on the atmospheric attenuation of different weather condition.

中文翻译：

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带故障保护的环形拓扑双向光纤接入网络中 FSO 流量的集成

在这项工作中，我们首先提出并演示了一种双向时分复用 (TDM) 自由空间光通信 (FSO) 流量与光纤故障保护集成在基于环的光纤接入网络中。在这里，当我们分别在中心局（CO）和每个光无线单元（OWU）添加新设计的光器件时，TDM-FSO光纤系统可以实现故障自保护运行。此外，根据提议的基于环的光纤网络，可以为对称的 10 Gbps 开关键控 (OOK) FSO 下行和上行连接提供最大数量的 8 个 OWU。因此，建议的 FSO 接入网络可以允许 25 公里的光纤传输和适当的 FSO 传输长度，具体取决于不同天气条件的大气衰减。