What Is Co-Packaged Optics (CPO)?

The explosive growth of Artificial Intelligence (AI), machine learning, cloud computing, and high-performance computing (HPC) is placing unprecedented demands on data center networks. As network speeds evolve from 400G to 800G and move toward 1.6T and beyond, traditional pluggable optical transceivers are approaching their physical and power-efficiency limits.

To overcome these challenges, the industry is increasingly turning its attention to Co-Packaged Optics (CPO)—a revolutionary optical interconnect architecture designed to support the next generation of AI and hyperscale networking infrastructure.

CPO is widely regarded as one of the most promising technologies for enabling future high-bandwidth, low-power, and highly scalable network architectures.

What Is Co-Packaged Optics (CPO)?

Co-Packaged Optics (CPO) is an advanced networking technology that integrates optical engines directly alongside switching ASICs or processing chips within the same package.

In traditional networking systems, electrical signals travel from the switch chip through PCB traces to pluggable optical transceivers located at the front panel of a switch. As bandwidth increases, these electrical pathways become a significant source of power consumption, signal degradation, and thermal challenges.

CPO eliminates much of this electrical distance by positioning optical components closer to the switching silicon.

The result is:

• Lower power consumption

• Improved signal integrity

• Reduced latency

• Higher bandwidth density

• Better scalability for future networking speeds

Why Traditional Optics Are Reaching Their Limits

The growth of AI infrastructure is driving massive increases in network bandwidth requirements.

Large AI training clusters often contain thousands of GPUs exchanging enormous volumes of data in real time.

As switch capacities evolve toward:

• 51.2T Ethernet switches

• 102.4T Ethernet switches

• Future 204.8T platforms

Traditional pluggable optics face several challenges:

●Increased Power Consumption

High-speed SerDes interfaces require more power as electrical transmission distances increase.

●Signal Integrity Challenges

Maintaining clean electrical signals across long PCB traces becomes increasingly difficult at 800G and 1.6T speeds.

●Front Panel Density Constraints

Modern switches require hundreds of optical connections, creating mechanical and thermal limitations.

●Cooling Complexity

Higher optical density generates more heat, increasing cooling requirements and operational costs.

These limitations are accelerating the industry's interest in CPO architectures.

How CPO Works

In a CPO design, optical engines are positioned directly adjacent to the switch ASIC.

Instead of transmitting high-speed electrical signals across the entire switch board, data is converted into optical signals almost immediately after leaving the chip.

This architecture significantly reduces:

• Electrical path length

• Signal loss

• Power consumption

• Electromagnetic interference

The optical signals are then transmitted through external fiber connections to other network devices.

By minimizing electrical transmission distances, CPO enables more efficient operation at ultra-high bandwidths.

Why CPO Matters for AI Data Centers

Supporting Massive AI Clusters

Modern AI models require thousands of interconnected GPUs.

Network performance directly impacts training efficiency, making low-latency and high-bandwidth communication essential.

CPO helps remove communication bottlenecks and supports larger AI deployments.

Reducing Power Consumption

Power efficiency has become one of the most critical concerns for hyperscale data centers.

Industry analysts estimate that CPO could reduce networking power consumption by 20% to 40% compared with traditional pluggable optics in certain deployment scenarios.

Enabling Future 1.6T and Beyond

While 800G optics are becoming mainstream today, future AI infrastructures will require even higher speeds.

CPO is viewed as a key enabling technology for:

• 1.6T Ethernet

• 3.2T Optical Interconnects

• Ultra-large AI Fabrics

CPO vs Traditional Pluggable Optics

While CPO represents the future direction of ultra-high-speed networking, pluggable optical transceivers remain the dominant technology today.

For current AI and cloud data center deployments, solutions such as:

• 400G QSFP-DD

• 800G QSFP-DD

• 800G OSFP

continue to provide excellent flexibility, interoperability, and deployment simplicity.

For example, C-LIGHT offers a comprehensive portfolio of 400G and 800G optical transceivers designed for AI clusters, cloud infrastructure, and high-performance data center networks. These solutions enable customers to build scalable networks today while preparing for future CPO-based architectures.

In addition, C-LIGHT's MPO/MTP fiber cabling systems and high-density optical connectivity solutions provide the physical infrastructure required to support next-generation AI networking environments.

Challenges Facing CPO Adoption

Although CPO offers significant advantages, several challenges remain:

Higher Manufacturing Complexity

Integrating optics and switching silicon within the same package increases design and production complexity.

Maintenance Considerations

Unlike pluggable optics, replacing failed optical components in a CPO system may require more extensive servicing.

Ecosystem Maturity

Industry standards, testing procedures, and interoperability frameworks are still evolving.

As a result, widespread deployment will likely occur gradually over the next several years.

The Future of Optical Networking

The networking industry is entering a period of rapid transformation driven by AI.

As bandwidth requirements continue to increase, optical interconnect technologies will play an increasingly critical role in data center architecture.

While pluggable optics will remain the primary solution throughout the current 800G generation, Co-Packaged Optics is expected to become a key technology for future 1.6T and higher-speed networks.

Organizations planning long-term AI infrastructure strategies should closely monitor CPO developments while continuing to deploy proven high-speed optical solutions available today.

Co-Packaged Optics (CPO) represents a major evolution in optical networking technology.

By bringing optical engines closer to switching silicon, CPO can reduce power consumption, improve signal integrity, and support the massive bandwidth requirements of future AI and hyperscale data centers.

Although traditional 400G and 800G optical transceivers remain essential today, CPO is poised to become a foundational technology for the next generation of AI networking infrastructure.

As the industry moves toward 1.6T and beyond, companies that understand and prepare for CPO adoption will be better positioned to build scalable, efficient, and future-ready networks.