AI Data Center Optical Interconnects: The Space Architecture Shift of XPO and CPO
AI AI Infrastructure Is Entering an Era Defined by Space and Thermal Density
As AI systems continue to scale, data center bottlenecks are no longer driven solely by compute performance or bandwidth limitations. Increasingly, the real constraints are becoming physical in nature.
The focus of system architecture is shifting from pure electrical and signal efficiency toward the co-design of space utilization and thermal management. At the switch level, this evolution is becoming increasingly evident through two emerging architectural paths: XPO and CPO.
| XPO：Extending the Pluggable Ecosystem Through Higher Density | CPO: The Path Toward Highly Integrated Optical Interconnects |
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In contrast, eXtra-dense Pluggable Optics (XPO) takes a different architectural approach. Rather than changing the fundamental pluggable framework, XPO expands upon the existing ecosystem by enhancing both density and thermal capability. Its design objectives are focused on:
At its core, XPO is fundamentally about: Maximizing the utilization of existing space without altering the underlying system architecture. This approach allows XPO to be integrated more easily into existing supply chains and system designs, making it a practical evolutionary path for AI Data Center infrastructure |
The core concept behind Co-Packaged Optics (CPO) is to integrate optical components directly adjacent to the ASIC package, minimizing the transmission distance of high-speed electrical signals. Its primary design objectives include:
At its core, CPO represents a package-level integration strategy, leveraging tight integration to redefine electrical signal paths across the PCB. However, as the level of integration increases, it also introduces greater challenges in manufacturing and serviceability.
As a result, CPO is generally viewed as an architecture optimized for maximum efficiency through deep integration. |
Both Architectures Are Ultimately Solving the Same Problem！
Although XPO and CPO follow different technological paths, they are not fundamentally competing approaches. Rather, they represent different solutions to the same underlying bottleneck.
The shared challenge is:
How can we accommodate high-speed optical interconnects, power requirements, and thermal demands within the limited space of a PCB and front panel?
Within this framework:
Each represents a different architectural response to the physical limits emerging in AI infrastructure.
AI Data Center Market Trends
The prevailing industry view is that, in the short to mid-term, architectures such as XPO, NPO (Near-Packaged Optics), and various forms of Pluggable Optics will continue to dominate AI Data Center deployments, while rapidly evolving toward higher bandwidth and greater density.
The key reason is that modular architectures still offer significant advantages in:
- System serviceability
- Supply chain flexibility
- Deployment maturity
- Large-scale scalability
However, as switch ASIC bandwidth and #SerDes lane speeds continue to increase, high-speed electrical paths across PCBs will face growing challenges related to:
- Signal loss
- Power consumption
- Routing complexity
- Thermal density
Under these conditions, CPO (Co-Packaged Optics)—by reducing electrical interconnect distance and improving packaging integration efficiency—may gradually become more important in future ultra-high-bandwidth AI systems.
That said, the market increasingly views the relationship differently:
XPO and CPO are not expected to replace one another. Instead, they are likely to coexist long-term across different bandwidth generations, system scales, and deployment scenarios.
The Supply Chain Is Entering a New Phase of Specialization？
As XPO architectures gain traction, the industry value chain is also beginning to evolve.
Beyond optical design itself, several capabilities are becoming increasingly critical:
- High-power Power Delivery design
- Liquid cooling and cold plate architecture design
- High-density mechanical integration
- High-speed interconnect and high-current transmission design
Within this trend, Nextron's manufacturing capabilities can naturally extend into the XPO module ecosystem, particularly in areas such as:
- AI server power delivery integration
- Liquid cooling cold plate manufacturing
- High-speed, high-current interconnect design
- AI infrastructure electromechanical integration
These capabilities enable end-to-end technical support—from design development through scalable manufacturing deployment.
Conclusion
XPO / High-Density Pluggable Optics
l Introducing XPO: Pluggable Optics for AI Networking
l XPO vs CPO: The Trade-offs Between Speed, Power, and Modularity in Next-Gen AI Networking
CPO / Co-Packaged Optics
