Emerging Trends in 400G and 800G: Low-Power Solutions for High-Speed Networks

As Serdes technology drives data centers into the era of 400G and 800G, port power consumption has become a hot topic in the industry. Low-power 400G/800G interconnection solutions have been successively introduced, attracting wide attention in the industry and being widely regarded as a key technology for AI and machine learning in smart data centers.

1. CPO Aims to Address Next-Generation Bandwidth and Power Challenges

With the continuous acceleration of bandwidth in network and computing structures, innovation is required in system and chip architecture to mitigate the slowdown of Moore’s Law. Meanwhile, copper interconnects are rapidly reaching their bandwidth distance limits. Silicon photonics is crucial for sustaining rapid data growth and high-bandwidth applications. Co-Packaged Optics (CPO) involves co-packaging switch chip ASICs and optoelectronic engines (optical transceivers) on the same substrate, with the optical engines placed as close to the ASIC as possible to minimize high-speed electrical channel losses and impedance discontinuities. This enables the use of faster, lower-power off-chip I/O drivers. Using CPO not only achieves networking but also facilitates GPU-to-GPU interconnects, resource pooling, and memory disaggregation. It meets the requirements of AI/ML training clusters with high bandwidth and radix connections, the lowest per-bit cost, and the highest power efficiency.

2. Linear Direct-Drive Pluggable Modules Also Reduce Power Consumption

In the era of 400G and 800G, in addition to pluggable optical modules and CPO solutions, Linear Direct Drive (also known as linear drive) pluggable 400G/800G optical modules became a research hotspot at OFC in March of this year. The biggest advantage of this optical module solution is that it eliminates the need for DSP chips, significantly reducing the power consumption and latency of signal processing at the module level.

GPU servers serving applications such as AI and machine learning provide excellent computing power but also result in increased server power consumption. The high-speed interconnection of 400G/800G leads to a corresponding increase in the power consumption of optical modules and network equipment. Both CPO and linear direct-drive pluggable modules may be interconnection solutions for future smart data centers, providing the lowest system-level power by eliminating all possible active components from the interconnect.