Yingyu Chen, Jinkai Zhou, Yaolin Wu, Hanyu Gao, Yongguang Xiao, Bofan Guo, Jinpei Li, Wenhao Li, Ruqi Chen, Runzhou Qiu, Jiajing Tu, Cheng Du, Lei Shen, X. C. Xie, Yuelin Yan, Guangquan Wang, Ying Yu, Zhengyong Liu, Shecheng Gao, Zhaohui Li, Chao Lu
Space division multiplexing (SDM), particularly multi-core fiber (MCF) technology, represents a promising solution for high-density cabling in duct-constrained scenarios such as submarine cable systems. Although recent laboratory experiments and prototype trials have demonstrated the feasibility of MCF-based submarine cables, a complete optical communication validation of a real-world MCF submarine cable link incorporating optical amplifiers has remained a critical necessity. Here, we demonstrate a field validation of the MCF submarine cable communication with an end-to-end system. Based on a field-deployed 7-core fiber submarine cable infrastructure, we achieved a record-breaking net transmission rate of 410.5 Tbit·s-1 over a 140 km 7-core fiber cable link by employing the matched C + L Band cladding-pumped 7-core MC-EDFA. The measurements indicate slight variation in attenuation and crosstalk compared to the pre-cabling conditions, confirming the MCF’s robustness to deployment and submarine disturbances. Furthermore, the developed 7-core MC-EDFAs maintain gains above ~18 dB and ~21 dB over the full C and L Bands, respectively, at an input power of −5 dBm, effectively compensating for span losses of submarine fiber cable. This successful field demonstration marks a crucial step towards the commercial implementation of integrated MC-EDFA SDM submarine optical communication systems for practical high-capacity applications. SDM based on multi-core fiber is a promising approach for capacity scaling in submarine cables. Yingyu Chen, Jinkai Zhou, and colleagues report the field validation of a deployed 7-core fiber submarine link, achieving 410.5 Tbit/s over 140 km with C + L band cladding-pumped MC-EDFAs.