Xing Zhenping, Samani Alireza, Xiang Meng, El-Fiky Eslam, Hoang Thang M, Patel David, Li Rui, Qiu Meng, Saber Md Ghulam, Morsy-Osman Mohamed, Plant David V
Opt Express. 2018 Sep 3;26(18):23969-23979. doi: 10.1364/OE.26.023969.
We experimentally demonstrate a digital-to-analog-converter-less (DAC-less) vestigial sideband (VSB) 4-level pulse amplitude modulation (PAM4) transmission system for data center interconnects (DCIs) using a silicon photonic (SiP) multi-electrode Mach-Zehnder modulator (ME-MZM) based DAC-less transmitter and a VSB self-coherent receiver. The impacts of linear and nonlinear impairments on the proposed system and their mitigation methods are comprehensively studied. By using Kramer-Kronig (KK) detection, frequency domain chromatic dispersion compensation, and short-memory time domain Volterra equalization at the receiver, we report a 112 Gb/s PAM4 transmission over 40 km standard single mode fiber (SSMF) with a bit error rate (BER) below the 7% overhead (OH) hard-decision forward error correction threshold of 3.8 × 10, and a 120 Gb/s PAM4 transmission over 80 km SSMF with a BER below the 20% OH soft-decision forward error correction threshold of 2 × 10, without any transmitter side digital signal processing such as pre-emphasis and pulse shaping.
我们通过实验展示了一种用于数据中心互连（DCI）的无数模转换器（DAC-less）残留边带（VSB）4电平脉冲幅度调制（PAM4）传输系统，该系统使用基于硅光子（SiP）多电极马赫-曾德尔调制器（ME-MZM）的无DAC发射器和VSB自相干接收器。全面研究了线性和非线性损伤对所提出系统的影响及其缓解方法。通过在接收器处使用克莱默-克朗尼格（KK）检测、频域色散补偿和短记忆时域沃尔泰拉均衡，我们报告了在40 km标准单模光纤（SSMF）上实现112 Gb/s PAM4传输，误码率（BER）低于3.8×10的7%开销（OH）硬判决前向纠错阈值，以及在80 km SSMF上实现120 Gb/s PAM4传输，误码率低于2×10的20% OH软判决前向纠错阈值，且无需任何发射器侧数字信号处理，如预加重和脉冲整形。
