Abstract

New transmission techniques for short-reach optical transmission applications especially datacenter interconnections are highly expected to break current bandwidth bottleneck, among which mode division multiplexing (MDM) based on few-mode fiber (FMF) is promising by exploring different linearly-polarized (LP) modes as spatial transmission channels. In this paper, an FMF design utilizing multiple-ring perturbations in fiber core to suppress modal crosstalk during fiber transmission is firstly proposed and a 6-LP-mode double-ring-core (DRC) FMF is fabricated with a high minimum refractive index difference of 1.49 × 10⁻³ among all LP modes. Secondly, a novel degenerate-mode-selective coupler (DMSC) converting each degenerate LPlm (l > 0) mode into the LP₁₁ mode in a two-mode fiber is proposed. Then intensity-modulation/direct-detection (IM/DD) MDM transmission scheme without any digital signal processing (DSP) can be realized utilizing mode multiplexer/demultiplexer (MUX/DEMUX) consisting of cascaded all-fiber mode-selective couplers (MSC) and DMSCs, in which each degenerate or non-degenerate LP mode is considered as an independent transmission channel. Based on the proposed DRC-FMF and mode MUX/DEMUX, we demonstrate a 4-LP-mode MDM prototype system using commercial single-mode 10-Gbps SFP + modules and 4K video transceivers without any hardware or software modifications. Finally, the intra-LP-mode dispersion effect in a weakly-coupled FMF is analyzed and a modified fixed-analyzer method is proposed for its measurement. Experimental results show that it may be one of the major impairments for IM/DD MDM transmission.

Prototype system for real-time IM/DD MDM transmission based on multiple-ring-core FMF and degenerate-mode-selective reception

Yuyang Gao, Dawei Ge, Jian Cui, Junchi Jia, Yongqi He, Zhangyuan Chen, Guifang Li, and Juhao Li
Opt. Express 27(26) 38281-38288 (2019)

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)

Low-modal-crosstalk orthogonal combine reception for degenerate modes in IM/DD MDM transmission

Jian Cui, Yuyang Gao, Shuailuo Huang, Jinyi Yu, Lei Shen, Lei Zhang, Changkun Yan, Liubo Yang, Ruichun Wang, Yongqi He, Zhangyuan Chen, and Juhao Li
Opt. Express 31(5) 8586-8594 (2023)

Weakly-coupled 7-core-2-LP-mode transmission using commercial SFP + transceivers enabled by all-fiber spatial multiplexer and demultiplexer

Yuyang Gao, Jian Cui, Junchi Jia, Dawei Ge, Chunyan Du, Yichi Zhang, Huang Yu, Zhengbin Li, Yongqi He, Zhangyuan Chen, and Juhao Li
Opt. Express 27(11) 16271-16280 (2019)

DSP-free ‘coherent-lite’ transceiver for next generation single wavelength optical intra-datacenter interconnects

Mohamed Morsy-Osman, Mohammed Sowailem, Eslam El-Fiky, Tristan Goodwill, Thang Hoang, Stephane Lessard, and David V. Plant
Opt. Express 26(7) 8890-8903 (2018)