ABSTRACT
Due to the rise of 5G, IoT, AI, and high-performance computing applications, datacenter traffic has grown at a compound annual growth rate of nearly 30%. Furthermore, nearly three-fourths of the datacenter traffic resides within datacenters. The conventional pluggable optics increases at a much slower rate than that of datacenter traffic. The gap between application requirements and the capability of conventional pluggable optics keeps increasing, a trend that is unsustainable. Co-packaged optics (CPO) is a disruptive approach to increasing the interconnecting bandwidth density and energy efficiency by dramatically shortening the electrical link length through advanced packaging and co-optimization of electronics and photonics. CPO is widely regarded as a promising solution for future datacenter interconnections, and silicon platform is the most promising platform for large-scale integration. Leading international companies (e.g., Intel, Broadcom and IBM) have heavily investigated in CPO technology, an inter-disciplinary research field that involves photonic devices, integrated circuits design, packaging, photonic device modeling, electronic-photonic co-simulation, applications, and standardization. This review aims to provide the readers a comprehensive overview of the state-of-the-art progress of CPO in silicon platform, identify the key challenges, and point out the potential solutions, hoping to encourage collaboration between different research fields to accelerate the development of CPO technology.
ABSTRACT
Electrical crosstalk severely degrades the performance of Mach-Zehnder modulator (MZM) array. However, conventional crosstalk suppression techniques incur losses of large amounts of chip area for signal isolation, which becomes a bottleneck of high-density electronic-photonic integrated circuit. In this paper, the electrical crosstalk of Traveling-Wave MZM array is originally analyzed with static and dynamic combined crosstalk coefficients. Circuit-level suppression techniques of differential dual-drive electrode schemes with tightly coupled electrode pairs and a virtual ground structure with full-matching termination circuit are investigated for noise-removing effects. Simulation results show that the dynamic electrical crosstalk coefficient between two adjacent modulators is reduced to below 1.5%, which is five times lower than the baseline. The electro-optical link measurements show that the BER is significantly reduced from 1E-3 to 1E-12 for multi-channel operation, which confirms the effectiveness of the crosstalk suppression techniques.
