The surge in demand for 800G optical modules is closely related to the changes in data center network architecture. The traditional three-layer architecture (including access layer, aggregation layer, and core layer) has been the standard for many years. With the continuous expansion of AI technology scale and east-west traffic, data center network architecture is also evolving. In the traditional three-layer topology, data exchange between servers needs to go through access switches, aggregation switches, and core switches, which puts tremendous pressure on aggregation switches and core switches.

If the server cluster continues to expand according to the traditional three-layer topology, high-performance equipment will need to be deployed in the core layer and the aggregation layer, resulting in a significant increase in equipment costs. This is where the new Spine-Leaf topology comes into play, flattening the traditional three-layer topology into a two-layer architecture. The adoption of 800G optical modules has promoted the emergence of the Spine-Leaf network architecture, which has many advantages such as high bandwidth utilization, excellent scalability, predictable network latency, and enhanced security.

In this architecture, leaf switches act as access switches in a traditional three-layer architecture and are directly connected to servers. Spine switches act as core switches, but they are directly connected to leaf switches, and each spine switch needs to be connected to all leaf switches.

The number of downlink ports on a leaf switch determines the number of leaf switches, while the number of uplink ports on a leaf switch determines the number of spine switches. Together, they determine the scale of the spine-leaf network.

The Leaf-Spine architecture significantly improves the efficiency of data transmission between servers. When the number of servers needs to be expanded, the scalability of the data center can be enhanced by simply increasing the number of Spine switches. The only drawback is that the Spine-Leaf architecture requires a large number of ports compared to the traditional three-layer topology. Therefore, servers and switches require more optical modules for fiber optic communications, stimulating the demand for 800G optical modules.

3Coptics 800G optical module

To cope with the surging demand for 800G optical modules, 3Coptics has successively launched short-distance 800G VR8/SR8 optical modules/AOC based on VCSEL lasers and 800G DR8/DR8+/DR8++ optical modules based on silicon photonics technology. 3Coptics' silicon photonic modules and multimode VCSEL optical modules constitute a complete interconnect solution for high-speed AI data centers.

The multimode series 800G optical modules/AOCs are equipped with high-performance 112Gbps VCSEL lasers and 7nm DSPs. The electrical host interface is 112Gbps PAM4 signals per channel and supports CMIS 4.0 protocol. Using QSFP-DD and OSFP packaging, VR8 supports 30m (OM3 MMF) and 50m (OM4 MMF) transmission distances; SR8 supports 60m (OM3 MMF) and 100m (OM4 MMF) transmission distances. There are two interfaces, MPO16 and 2×MPO12, to choose from, suitable for short-distance data center application scenarios.

Silicon photonic modules focus on solving interconnection scenarios with links over 100 meters. 3Coptics silicon photonics 800G DR8 uses QSFP-DD or OSFP packaging. DR8 has a transmission distance of 500m, DR8+ can transmit 2km, and DR8++ can transmit 10km. The module uses four 1310nm CW lasers; the maximum power consumption is less than 18W. The currently released version supports two connector architectures: MPO16/APC and Dual MPO12/APC. Compared with the conventional 8-way EML solution 800G optical module, silicon photonic modules can use fewer lasers. For example, 800G DR8 can use 1 laser to achieve lower power consumption performance. This year, 3Coptics will also launch 800G QSFP-DD PSM DWDM8 and 800G OSFP/QSFP-DD 2×FR4 optical modules based on silicon photonics to provide customers with more choices.

The adoption of 800G optical modules not only addresses current challenges, but also provides forward-looking solutions to accommodate the expected growth in data processing and transmission. As technology advances, the synergy between artificial intelligence computing and high-speed optical communications will play a key role in shaping the future of information technology infrastructure.