Abstract

Determining how to add more signal channels without enlarging the cable volume is continually an issue in managing submarine cables. To improve the cost per bit and the power efficiency, space division multiplexing (SDM) is regarded as a promising solution that could be used to address optical density and cable capacity challenges regarding submarine cables. In this study, we focus on angular momentum (OAM) modes supporting few-mode ring-core fiber (RCF) solutions for submarine cables. Considering the inhibition of the hydrogen loss for the submarine cable, we propose a center-region-lifted 3-OAM-mode-group supporting RCF (abbreviated to 3-OAM-MG RCF) with a core-cladding index contrast of 0.6 ${\%}$ , and meanwhile we also design and fabricate a matched 3-OAM-MG erbium-doped fiber (EDF). To confirm the short-haul transmission ability, we conduct a wavelength/mode/polarization division multiplexing (WDM-MDM-PDM) transmission test through a 25.3-km 3-OAM-MG RCF, where the coupled modes inside MG are demultiplexed by using 2 × 2 multiple-input multiple-out (MIMO) equalization. The transmission capacity is approximately 35 Tbit/s and the bit error rates (BERs) of all the channels are less than 2.4 $\times 10^{-2}$ . For the application scenario of long-haul submarine communication, a cascade WDM-MDM transmission system consisting of 3-OAM-MG RCF and 3-OAM-MG EDF is set up, which makes the BERs of all the mode and wavelength channels below the 20 ${\%}$ soft-decision forward error correction (SD-FEC) threshold. It indicates that data-carrying OAM mode multiplexing transmission has potential application in a long-haul submarine cable system.

1120-channel OAM-MDM-WDM transmission over a 100-km single-span ring-core fiber using low-complexity 4×4 MIMO equalization

Junyi Liu, Zhenrui Lin, He Zhu, Lei Shen, Shuqi Mo, Zhenhua Li, Jingxing Zhang, Junwei Zhang, Xiaobo Lan, Jie Liu, and Siyuan Yu
Opt. Express 30(11) 18199-18207 (2022)

Mode-division multiplexed transmission of wavelength-division multiplexing signals over a 100-km single-span orbital angular momentum fiber

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Photon. Res. 8(7) 1236-1242 (2020)

Weakly guiding graded-index ring-core fiber supporting 16-channel long distance mode division multiplexing systems based on OAM modes with low MIMO-DSP complexity

Xi Zhang, Shi Chen, and Jian Wang
Opt. Express 30(20) 35828-35839 (2022)

18 km low-crosstalk OAM + WDM transmission with 224 individual channels enabled by a ring-core fiber with large high-order mode group separation

Long Zhu, Guoxuan Zhu, Andong Wang, Lulu Wang, Jianzhou Ai, Shi Chen, Cheng Du, Jie Liu, Siyuan Yu, and Jian Wang
Opt. Lett. 43(8) 1890-1893 (2018)

Evaluating the coupling efficiency of OAM beams into ring-core optical fibers

Santiago Rojas-Rojas, Gustavo Cañas, Gabriel Saavedra, Esteban S. Gómez, Stephen P. Walborn, and Gustavo Lima
Opt. Express 29(15) 23381-23392 (2021)