A 50-Gb/s Optical Transmitter Based on Co-design of a 45-nm CMOS SOI Distributed Driver and 90-nm Silicon Photonic Mach-Zehnder Modulator

This paper presents an integrated optical driver and Mach-Zehnder modulator (MZM) that operates to 50 Gb/$s$. The MZM consists of 4 traveling wave segments along a 3.2 mm length in a 90-nm Silicon Photonic (SiP) technology. The broadband distributed amplifier is a pseudo-differential design with 3-stack driver stages to deliver sufficient voltage swing in a 45nm CMOS SOI technology. The optical eye is open to 50 Gb/$s$ and indicates error-free operation to 30 Gb/$s$. The total circuit consumes 480 mW.

I. Introduction

Silicon photonics (SiP) offer a low-cost platform for large-scale optical systems, and find applications in data-centers, long-haul optical networks, and microwave photonics. However, high-speed electro-optical (E/O) modulation requires separate electronic and photonic device technologies. The SiP Mach-Zehnder Modulator (MZM) is constructed with p-n junction phase shifters that produce a 180 degree phase shift at the voltage. Due to the relatively low product for SiP MZMs (∼ 1.5 V-cm), the driver should produce around 3–5 Vpp differential voltage swing.