Abstract

The mode-division-multiplexing (MDM) transmission technique using a few-mode fiber (FMF) has been investigated to overcome the theoretical limitation of the transmission capacity of a single-mode fiber. In MDM transmission, multiple-input multiple-output (MIMO) digital signal processing (DSP) is generally required on the receiver side to compensate for the modal crosstalk (XT) between the spatial modes. However, the computational cost is high, especially for high-order MDM systems that use many spatial modes. To reduce the MIMO matrix size, MDM transmission with partial MIMO-based DSP has been proposed using weakly coupled FMFs. The modal XT in such fibers can be suppressed by a special fiber design; however, the modal XT still remains and strongly limits the signal-to-noise-ratio (SNR) and capacity. To further increase the capacity for a given SNR, an optimization of the modulation format is significant. Recently, probabilistic shaping (PS) has received attention since it can gradually change the entropy of a modulation format and maximize the capacity for a given SNR. In this article, we demonstrate weakly coupled 10-mode-multiplexed transmission with four 4 × 4 MIMOs and two 2 × 2 MIMOs using rate-adaptive PS-16QAM signals over 48-km FMF, achieving a record transmission capacity of 402.7 Tb/s in 125-μm cladding single-core fiber transmission experiments. Furthermore, we also show the possibility of a further capacity increase by adjusting the entropies of the PS-16QAM signals depending on the spatial mode.

Long-haul intermodal-MIMO-free MDM transmission based on a weakly coupled multiple-ring-core few-mode fiber

Mingqing Zuo, Dawei Ge, JiaXin Liu, Yuyang Gao, Lei Shen, Xiaobo Lan, Zhangyuan Chen, Yongqi He, and Juhao Li
Opt. Express 30(4) 5868-5878 (2022)

Wavelength-interleaved MDM-WDM transmission over weakly-coupled FMF

Yu Tian, Juhao Li, Zhongying Wu, Yuanxiang Chen, Paikun Zhu, Ruizhi Tang, Qi Mo, Yongqi He, and Zhangyuan Chen
Opt. Express 25(14) 16603-16617 (2017)

MDM transmission of CAP-16 signals over 1.1- km anti-bending trench-assisted elliptical-core few-mode fiber in passive optical networks

Lulu Wang, Jianzhou Ai, Long Zhu, Andong Wang, Songnian Fu, Cheng Du, Qi Mo, and Jian Wang
Opt. Express 25(19) 22991-23002 (2017)

Weakly-coupled 4-mode step-index FMF and demonstration of IM/DD MDM transmission

Tao Hu, Juhao Li, Dawei Ge, Zhongying Wu, Yu Tian, Lei Shen, Yaping Liu, Su Chen, Zhengbin Li, Yongqi He, and Zhangyuan Chen
Opt. Express 26(7) 8356-8363 (2018)

Mode-division-multiplexing self-homodyne coherent transmission over a weakly coupled few-mode fiber for optical interconnections

Gang Qiao, Chengbin Long, Yu Yang, Zhaopeng Xu, Mingqing Zuo, Qi Wu, Shangcheng Wang, Lulu Liu, Lei Shen, Jie Luo, Zhixue He, Honglin Ji, Weisheng Hu, Zhangyuan Chen, and Juhao Li
Opt. Lett. 49(4) 981-984 (2024)