Corning Contributes to Broadcom’s TH5 Bailly Co-Packaged Optics System
Benoit Fleury
Published: June 12, 2025
The data center industry is undergoing a surge of optical infrastructure innovation specifically around co-packaged optics (CPO). Although this technology has been around for quite some time, the explosion of AI and its required networking infrastructure has caused data centers to evolve very quickly to meet the heightened data processing capacities and speeds needed to support growing AI models. CPO is seen as the next great wave to support AI-driven growth as it enables significant leaps in networking and processing speed, density, and power efficiency which are all needed to meet the needs of AI’s insatiable data demands.
CPO effectively bundles optical transceivers closer to the networking (or processing) chips, thereby reducing the length of the electrical paths between the two. In an environment where speed and bandwidth are intricately linked, this short distance – a matter of mere inches – makes all the difference.
Scaling is also critical as data center operators look to build-out infrastructure that is future-proofed. Ethernet speeds and switching bandwidths tend to double every couple of years, so to keep pace with the increase of both adoption and the complexity of AI tools, companies like Broadcom are reimagining how optical connectivity is designed and deployed inside high-performance switch environments. Corning and Broadcom have been collaborating for several years on CPO optical connectivity. Most recently, Broadcom announced the Bailly system, the industry’s first fully CPO-based 51.2 terabit per second (Tb/s) Ethernet switch. Corning’s contribution to the Bailly is not only our optical componentry, but it is also our vast experience in creating dense-and-reliable fiber deployment structures, for which AI is increasingly dependent upon given how quickly it is evolving across data centers.
CPO technology and its underlying optical connectivity infrastructure is a significant breakthrough for the data center industry, particularly in terms of improving optical interconnection speeds and densities as needed to support increasingly large-scale AI clusters.
What makes the Bailly system unique
Unlike traditional switches that rely on pluggable optics at the faceplate, the Bailly system brings the optical connections directly inside the switch, putting them closer to the chips inside the box. By placing optics and electronics closer together, this solution enables higher interconnection speeds and bandwidth densities while improving power consumption efficiency. It is a fully integrated, high-capacity design — delivering 51.2 Tb/s of Ethernet switching bandwidth with eight co-packaged silicon photonics optical engines, each handling 6.4 Tb/s of optical interconnection.
At the heart of this system is an intricate high-density fiber infrastructure that contains Corning’s high precision fiber array units (FAUs), specialized fibers and high-density connectors that enable optical signals to connect directly to switch chips with unprecedented precision and reliability.
How Corning helps deliver precision and reliability
An important requirement of the Bailly system is the incredible accuracy needed in aligning each fiber to its corresponding waveguide, or channel, within the Photonic Integrated Circuits (PICs). Tight fiber-to-chip alignment tolerances are needed to minimize insertion loss and Corning meets this need with its high precision Photonic Grade FAUs. Delivering this level of precision at scale and reliably adds to the challenge, but Corning is well positioned to meet it, thanks to its engineering expertise and operational scale.
The reliability of the overall CPO system is critical for this technology to be broadly adopted, and Corning enables this by ensuring that the overall fiber infrastructure is designed and deployed with a high degree of robustness and reliability; the fiber harnesses that Corning provides include all of the “inside-the-box” optical connectivity elements from the FAUs connecting fibers to the chips to the optical connectors on the faceplate. Depending on the system capacity and optical architecture, hundreds or even thousands of fibers need to be deployed in a single CPO box or system, so in that context, the reliability of each optical link becomes very important. As you can see, designing and deploying CPO fiber infrastructures in a way that maximizes reliability and ease of assembly in high volumes is an important consideration—a shared proficiency that Corning and Broadcom have showcased through white papers and joint presentations in recent months.
Corning continues to bring new CPO innovations to the market by improving performance and density of optical infrastructures. For example, we recently launched the CPO FlexConnect™ fiber that is optimized for dense CPO systems by enabling tight bends for short “inside-the-box” deployments without the effect of multipath interference that can degrade optical performance.
As AI workloads continue to grow in complexity and scale, traditional data center technologies and architectures will not keep pace with the needed bandwidth, density, and power efficiency. By bringing optical connectivity much closer to the heart of data center switching and processing units, CPO-based infrastructures are poised to enable AI workloads to reach their full potential, and Corning will continue to collaborate with industry leaders like Broadcom to stay ahead of the curve in this rapidly evolving space.
