Optical Interconnect Adoption in AI Data Centers: What Is Slowing Down the Transition to CPO?

Why Optical Scale-Up Is Slower Than Expected

The industry narrative is clear: NVLink-based architectures are gaining traction, and Co-Packaged Optics (CPO) is often positioned as the next step in AI infrastructure evolution.

However, in real deployment terms, the transition to fiber-based scale-up is progressing more slowly than expected.

Based on current validation cycles and infrastructure readiness, large-scale adoption of optical interconnect architectures is unlikely before 2028.

This delay is not driven by limitations in physics—but by practical constraints in thermals, power density, and system-level economics.

Thermal Constraints and Reliability at High Power Density

As AI clusters scale, power density is approaching—and in some cases exceeding—100W/cm².

At this level, engineering challenges shift fundamentally:

• Thermal management becomes a system-level constraint rather than an optimization problem
• Reliability extends from individual components to full rack-level stability
• Cooling architecture begins to dictate system design decisions

In several validation scenarios, CPO-based systems already require advanced liquid cooling, forcing a redesign of rack-level infrastructure.

This is not a marginal upgrade—it is a structural change in how data centers are built.

Market Reality: Cautious Deployment Strategies

Across the industry, deployment strategies are becoming more conservative.

• Tier 1 hyperscalers are prioritizing validation over rapid rollout
• Tier 2 cloud providers and telecom operators are focusing on long-term reliability and operational risk

The question is no longer whether optical interconnects will dominate, but whether current solutions are ready for production-scale deployment.

OFC 2026: Innovation vs. Deployment Gap

At OFC 2026, emerging architectures such as Near-Package Optics (NPO) attracted strong attention.

From a technical perspective, NPO demonstrates clear potential:

• High-density integration
• Improved signal performance at 200G / 400G per lane

However, from a deployment standpoint, these solutions remain at the proof-of-concept stage and are not yet aligned with near-term production roadmaps.

This gap between innovation and deployability is one of the most critical friction points in the industry.

Early Validation Work Behind the Scenes

While large-scale deployment is still ahead, early-stage validation efforts are already underway.

ADTEK is working with industry partners to support evaluation of next-generation optical architectures, focusing on:

• Thermal validation under high-density conditions
• Laser reliability in real-world environments
• Forward-looking power architectures, including 800VDC systems

These are not theoretical exercises—they are essential prerequisites for scalable deployment.

A Structural Risk: Vendor Lock-In Returning

Beyond technical challenges, a structural concern is emerging.

Over the past decade, hyperscale infrastructure has shifted toward open and disaggregated architectures.

However, current CPO and NPO ecosystems show a different trend:

• Vertically integrated stacks
• Proprietary interfaces
• Limited interoperability

For telecom operators and regional cloud providers, this introduces potential risks in flexibility and long-term scalability.

After years of moving away from vendor lock-in, the industry may be facing a return to it.

What Can Be Deployed Today

While optical architectures define the future, current AI infrastructure must solve immediate deployment challenges.

Key focus areas include:

• Multi-fabric complexity across scale-up, scale-out, PCIe/CXL, and storage
• Signal integrity at 224G in high-density environments
• Stability of hybrid power systems (800VDC / 48VDC)

At present, many deployments still rely on copper-based solutions and high-speed connectivity products to ensure stable operation.

Bridging the Gap Between Today and the Optical Future

The long-term direction is clear: optical interconnects will play a central role in AI infrastructure.

However, the transition is not immediate.

Between today’s deployments and future optical architectures lies a critical phase of validation, system redesign, and ecosystem development.

ADTEK will continue to share insights from this transition, including upcoming technical research on early-stage CPO deployment.

Conclusion

The future of AI infrastructure is optical.

But the present is defined by what can be deployed reliably, economically, and at scale.

Today, that still means a combination of copper-based systems, hybrid architectures, and pragmatic engineering decisions.

Optical adoption is not a question of “if,” but “when”—and that timeline depends on solving real-world constraints, not just advancing technology.