30.6 A 6V Swing 3.6% THD >40GHz Driver with 4.5× Bandwidth Extension for a 272Gb/s Dual-Polarization 16-QAM Silicon Photonic Transmitter

• Published in: 2019 IEEE International Solid- State Circuits Conference - (ISSCC) pp. 484 - 486
• Main Authors: Ahmed, Abdelrahman H., Lim, Daihyun, Elmoznine, Abdellatif, Ma, Yangjin, Huynh, Tam, Williams, Christopher, Vera, Leonardo, Liu, Yang, Shi, Ruizhi, Streshinsky, Matthew, Novack, Ari, Ding, Ran, Younce, Rick, Sukkar, Rafid, Roman, Jose, Hochberg, Michael, Shekhar, Sudip, Rylyakov, Alexander
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.02.2019
• Subjects: BiCMOS integrated circuits; Capacitors; Integrated circuits; Linearity; Optical polarization; Photonics; Silicon
• ISSN: 2376-8606
• DOI: 10.1109/ISSCC.2019.8662318

Traditionally, the high-performance optical coherent communication TX has been a discrete assembly based on LiNbO 3 modulators and III-V drivers. While delivering high bandwidth (BW) and linearity, such a platform is bulky and does not work for high-volume or intra-datacenter applications. Silicon photonics (SiPh) offers a Si-based platform for next-generation transceivers by integrating all required optical functions. But even in existing SiPH-based commercial modules, the driver generally remains a III-V-based chipset, impeding the path to an all-silicon solution. The challenge for an all-silicon-based coherent optical TX is in the simultaneous requirement of high differential voltage swing (V ppd ), linearity and BW. In this work, we present a 130nmSiGe driver achieving a 6V ppd swing, 3.6% THD and small-signal BW over 40GHz. Co-packaged with a SiPh transceiver, the driver enables the same level of performance as LiNbO 3 modulators with III-V drivers and demonstrates 272Gb/s dual-polarization (DP)-160AM transmission. This is enabled using (1) circuit techniques that achieve a BW extension ratio (BWER) of 4.5\times for the Mach-Zehnder modulator (MZM) driver while simultaneously achieving large swing (\mathrm {V}_{\mathrm {p}\mathrm {p}\mathrm {d}}=6V), high linearity (THD =3.6%) and mitigating breakdown voltage (BV) and reliability concerns with large V ppd ; (2) pre-emphasis control in the driver output stage and gain control in the pre-driver VGA to compensate for the electro-optic (E/0) BW of the TX over corners; and (3) a monolithic integration of MZMs with a polarization rotator (PR) optimized for high-BW, low-crosstalk and co-integration with drivers for DP-OAM and DP-OPSK operation.