A Dual-Polarization Silicon-Photonic Coherent Transmitter Supporting 552 Gb/s/wavelength
A Dual-Polarization Silicon-Photonic Coherent Transmitter Supporting 552 Gb/s/wavelength
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DOI：
10.1109/jssc.2020.2988399
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发表时间：
2020-09-01
影响因子：
5.4
通讯作者：
Shekhar, Sudip
中科院分区：
文献类型：
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作者：
Ahmed, Abdelrahman H.;El Moznine, Abdellatif;Shekhar, Sudip
相干光链路使用诸如正交相移键控（QPSK）和正交幅度调制（QAM）之类的高级调制方案并且通过利用光的双偏振（DP）来相对于其强度调制直接检测（IM-DD）对应物提高频谱效率。这种频谱效率的提高也导致对链路组件的严格要求。发射机（TX）必须同时实现高带宽（BW）、线性度、输出摆幅和可靠性。在这篇文章中，我们提出了一个硅光子马赫-曾德尔调制器为基础的光发射机上的硅绝缘体（SOI）工艺，和线性，高摆幅的SiGe驱动器上的130纳米BiCMOS工艺。驱动器的输出级采用了电压击穿增强技术，以确保TX的可靠性。采用了基于电阻的电容分压技术，并辅以零峰化和负反馈等方法，实现了驱动器的增益、带宽、摆幅和线性度目标。该驱动器的差分摆幅为6 V峰峰值，总谐波失真（THD）为3.6%，电气带宽超过40 GHz。与硅光子调制器共同设计和共同封装的TX在6 V峰峰值驱动器摆幅下使用DP-16 QAM可实现272 Gb/s/波长，在2.4 V峰峰值驱动器摆幅下使用DP-16 QAM可实现超过0.5 Tb/s/波长的数据速率。低成本、紧凑型全Si/SiGe设计可满足采用34 Gbaud III-V驱动器的LiNbO 3调制器所需的光学SNR性能。
Coherent optical links improve spectral efficiency over their intensity-modulation direct-detect (IM-DD) counterparts using advanced modulation schemes such as quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM), and by utilizing dual polarization (DP) of light. This increase in spectral efficiency also leads to stringent requirements for the link components. The transmitter (TX) must simultaneously achieve high bandwidth (BW), linearity, output swing, and reliability. In this article, we present a silicon-photonic Mach-Zehnder modulator-based optical TX on an Silicon-on-Insulator (SOI) process, and linear, high-swing SiGe drivers on 130-nm BiCMOS process. The output stage of the driver uses a voltage breakdown enhancement technique to ensure the reliability of the TX. A resistor-based capacitor splitting technique is introduced, and aided by other methods such as zero-peaking and degeneration, the targeted gain, BW, swing, and linearity for the driver are realized. The driver achieves a differential swing of 6 V peak-to-peak, a total harmonic distortion (THD) of 3.6%, and more than 40 GHz of electrical BW. Co-designed and co-packaged with the silicon-photonic modulators, the TX achieves 272 Gb/s/wavelength with DP-16 QAM at 6-V peak-to-peak driver swing and exceeds 0.5 Tb/s/wavelength data rates with DP-16 QAM at 2.4-V peak-to-peak driver swing. The low-cost, compact, and all-Si/SiGe design matches the required optical SNR performance of LiNbO3 modulators with III-V drivers at 34 Gbaud.