摘要
针对跨洋光纤通信系统中存在严重的噪声累积和非线性效应等问题,将概率整形(PS)技
术与子载波复用(SCM)技术相结合以缓解跨洋传输链路损伤,进而实现系统传输性能的
提升。通过在商用 VPI 软件中搭建跨洋光纤传输仿真链路,对单载波和双子载波复用系统
进行仿真研究。仿真结果表明,在 20%的 FEC 阈值条件下,均匀(H=4)双子载波和 PS
(H=3.6,H=3.7,H=3.8)双子载波 PDM-16QAM 系统的传输距离相比均匀(H=4)单载
波 PDM-16QAM 系统分别提升了 2.3% (405 km)、21% (3698 km)、19.7%
(3468 km)和 14.5% (2549 km)。随后,搭建光纤环路传输实验平台,进一步验证所
提方案的可行性。实验结果表明,在 20% 的 FEC 阈值条件下,均匀双子载波和 PS
(H=3.8)双子载波 PDM-16QAM 系统的传输距离相比均匀单载波 PDM-16QAM 系统分
别提升了 5.6% (282 km)和 46.2% (2323 km)。仿真与实验结果表明,在跨洋光纤
通信系统中引入 PS 与 SCM 可有效提升系统的传输性能。
Abstract
Given the serious noise accumulation and the nonlinearity effect in transoceanic fiber
communication systems, probabilistic shaping (PS) and subcarrier multiplexing (SCM)
are combined to alleviate transoceanic transmission link impairments, so as to improve
the transmission performance of these systems. The single-carrier and dual-subcarrier
multiplexing systems are simulated by developing a simulation link of transoceanic fiber
transmission with the commercial software VPI. The simulation results show that the
transmission distances of the uniform (H=4) and PS (H=3.6, H=3.7, H=3.8) dual-
subcarrier PDM-16QAM systems are respectively 2.3% (405 km), 21% (3698 km), 19.7%
(3468 km), and 14.5% (2549 km) longer than that of the uniform (H=4) single-carrier
PDM-16QAM system under the 20% forward error correction (FEC) threshold. Then, an
experimental fiber loop transmission platform is built to verify the feasibility of the
proposed scheme. According to the experimental results, the transmission distances of
the uniform and PS (H=3.8) dual-subcarrier PDM-16QAM systems are respectively 5.6%
(282 km) and 46.2% (2323 km) longer than that of the uniform single-carrier PDM-
16QAM system under the 20% FEC threshold. In summary, both simulation and
experimental results demonstrate that applying PS and SCM to transoceanic fiber
communication systems can effectively enhance these systems' transmission
performance.
1 引言