双抽头光-数字前馈均衡实现IM/DD系统中的高速光传输
Dual-Tap Optical-Digital Feedforward Equalization Enabling High-Speed Optical Transmission in IM/DD Systems
AI总结：
针对高速IM/DD系统中光纤色散引发功率衰落、码间干扰限制传输距离的问题，提出双抽头光-数字前馈均衡方案，可有效补偿功率衰落，在15km标准单模光纤200Gb/s/λ PAM-4传输中满足7%硬判决FEC阈值，具备长距应用潜力。
摘要：
强度调制直接检测（IM/DD）传输凭借成本效益高、结构简单的优势，被广泛应用于高速光传输场景。但随着数据速率提升，光纤色散（CD）会引发严重的功率衰落效应，且直接检测会产生码间干扰（ISI）。此外，ISI会随着光纤长度增加而加剧，极大限制了IM/DD系统的传输距离。本文提出一种双抽头光-数字前馈均衡（DT-ODFE）方案，能够在保持低成本与简洁性的同时，有效补偿CD引发的功率衰落。本文构建了包含双抽头光均衡器的IM/DD传输理论信道响应，理论分析表明，对于采用1371nm波长、传输距离10km标准单模光纤（SSMF）的IM/DD传输，频率陷波从33.7GHz消除至46GHz。仿真结果显示，与仅采用符号间隔前馈均衡器（FFE）的IM/DD系统相比，DT-ODFE可实现2.3dB的信噪比（SNR）增益。当光纤长度增加至15km时，DT-ODFE仍表现优异，而FFE、判决反馈均衡器（DFE）和Volterra非线性均衡器（VNLE）均无法补偿功率衰落，且不满足7%硬判决前向纠错（FEC）阈值。对于15km SSMF上的200 Gb/s/λ PAM-4传输，结果表明，采用最优系数的所提DT-ODFE的SNR满足7%硬判决FEC阈值，展现出DT-ODFE在长距（LR）/固定距（FR）场景的高速IM/DD系统中的巨大潜力。
英文摘要：
Intensity-modulation and direct-detection (IM/DD) transmission is widely adopted for high-speed optical transmission scenarios due to its cost-effectiveness and simplicity. However, as the data rate increases, the fiber chromatic dispersion (CD) would induce a serious power fading effect, and direct detection could generate inter-symbol interference (ISI). Moreover, the ISI becomes more severe with the increase of fiber length, thereby highly restricting the transmission distance of IM/DD systems. This paper proposes a dual-tap optical-digital feedforward equalization (DT-ODFE) scheme, which could effectively compensate for CD-induced power fading while maintaining low cost and simplicity. A theoretical channel response is formulated for IM/DD transmission, incorporating a dual-tap optical equalizer, and the theoretical analysis reveals that for an IM/DD transmission using 1371nm over 10km standard single-mode fiber (SSMF), frequency notch is removed from 33.7GHz to 46GHz. Simulation results show that the DT- ODFE achieves an SNR gain of 2.3dB over IM/DD systems with symbol-space feedforward equalizer (FFE) alone. As the fiber length increases to 15 km, DT- ODFE performs well, while FFE, decision-feedback equalizer (DFE) and Volterra nonlinear equalizers (VNLE) all fail to compensate for the power fading and the 7% hard-decision FEC limit is not satisfied. For 200 Gb/s/$λ$ PAM-4 over 15km SSMF, results show that the signal-to-noise ratio (SNR) of the proposed DT- ODFE with optimal coefficients satisfies the 7% hard-decision FEC limit, which uncovers the great potential of the DT- ODFE for high-speed IM/DD systems in LR/FR scenarios.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
