Co-packaged optics (CPO) integrates optical engines directly with switch or compute chips, drastically reducing power consumption and increasing bandwidth density.

What is Co-Packaged Optics?

Co-packaged optics (CPO) is a networking architecture that places the optical engine—responsible for converting electrical signals into light—directly onto the switch chip's package, rather than in a removable front-panel transceiver . In traditional switches, the optical transceivers are connected via long copper traces, which introduce signal loss, require digital signal processing (DSP) for correction, and consume significant power. By moving the optical engine millimeters from the ASIC, CPO eliminates long electrical paths, reduces the need for DSP, and allows only fiber to exit the switch .

Key Benefits

• Power Efficiency: CPO reduces interconnect power consumption by up to 70–80% compared to traditional pluggable optics, dropping energy use from around 15 pJ/bit to near 5 pJ/bit .
• Bandwidth Density: Integrating optics close to the ASIC allows higher channel density, supporting massive switches (e.g., 51.2T or 102.4T) without being limited by front-panel space .
• Low Latency: Shorter electrical paths reduce signal degradation and latency, which is critical for AI and high-performance computing workloads .
• Thermal Management: Less power consumption translates to lower heat generation, reducing cooling requirements and supporting green data center initiatives .

Applications

CPO is particularly valuable in AI superclusters, high-performance computing (HPC), and large-scale data centers, where massive data transfer between GPUs or processing nodes is required . It addresses the power-performance wall faced by traditional pluggable optics and enables scaling of generative AI models and other data-intensive workloads.

Comparison with Other Optical Architectures

• Pluggable Optics: Traditional modules connected via front-panel interfaces; higher power consumption and longer electrical paths.
• Near-Packaged Optics (NPO): Optics placed close to the ASIC on the mainboard; offers some power savings but less integration than CPO .
• Extra-Dense Pluggable Optics (XPO): High-throughput front-panel modules; maintains serviceability but requires advanced cooling and DSP support . CPO represents a fundamental shift in switch design, requiring new manufacturing, cooling, and maintenance approaches, but it provides unmatched efficiency and scalability for next-generation data centers .