Co-packaged optics testing moves earlier as chipmakers try to prevent costly failures
Co-packaged optics, often called CPO, is becoming one of the most important technologies in the race to support faster data movement for AI, high-performance computing, and next-generation data centers. But as the industry pushes optical engines closer to advanced processors and switches, one major challenge is becoming impossible to ignore: testing.
At SEMICON Taiwan 2026, Jeff Lee, president of Chroma ATE’s Photonics and Precision business unit, highlighted how CPO is changing the traditional approach to semiconductor testing. Instead of waiting until the final package stage to identify defects, chipmakers and equipment suppliers are now being pushed to move optical testing earlier in the manufacturing flow.
The reason is simple. Optical testing takes time, and failures discovered too late can be extremely expensive.
In conventional semiconductor production, many electrical tests can be completed quickly and at scale. CPO introduces a different level of complexity because optical engines must be tested for performance, alignment, signal integrity, and long-term reliability. These optical components are tightly integrated with advanced chips, which means a failure at the final package stage could waste not only the optical module but also the expensive processor, substrate, and packaging work already completed.
That risk is driving a shift toward mid-stage testing. By screening optical engines before they reach final packaging, manufacturers can catch problems earlier and reduce the chance of scrapping high-value components later in the process.
CPO testing becomes a critical bottleneck
As demand grows for faster interconnects inside data centers, CPO is gaining attention as a potential solution to bandwidth and power challenges. By placing optical connections closer to the chip, CPO can help reduce energy loss and improve communication speed compared with traditional pluggable optical modules.
However, this tighter integration also makes production more difficult. Optical components are sensitive to alignment, temperature, and signal quality. Testing them requires specialized equipment and longer validation times than many standard chip tests.
This creates a bottleneck for manufacturers. If optical testing is delayed until the end of the production line, companies may face slower throughput and higher losses when defects are discovered late. Moving the test process to an earlier stage helps reduce that risk and gives manufacturers more control over yield.
Why mid-stage testing matters for advanced packaging
Advanced packaging has already become a key part of semiconductor innovation, especially for AI chips, networking processors, and high-bandwidth computing systems. CPO adds another layer of complexity because it combines electronic and photonic technologies inside a highly integrated package.
Mid-stage testing offers a more practical way to manage that complexity. Instead of treating optical validation as a final checkpoint, companies can use earlier screening to confirm that the optical engine meets performance requirements before it is combined with other expensive components.
This approach can help improve production efficiency in several ways. It can reduce waste, shorten failure analysis time, improve yield forecasting, and prevent defective optical engines from moving deeper into the manufacturing process.
For chipmakers, this is not just a technical adjustment. It is also an economic necessity. As advanced packages become more expensive, the cost of a late-stage failure continues to rise.
CPO adoption depends on reliable testing
The future of co-packaged optics will depend not only on design innovation but also on the ability to test products efficiently at scale. Data center operators and AI infrastructure providers need faster, more power-efficient connections, but manufacturers must be able to deliver CPO solutions with strong reliability and acceptable cost.
That makes test strategy a central part of CPO commercialization. Equipment suppliers are expected to play a major role by developing platforms that can handle optical testing earlier, faster, and with greater precision.
As CPO moves closer to volume production, the industry is likely to see more investment in photonics test systems, automated alignment tools, and integrated inspection solutions. Companies that can solve the testing bottleneck may gain an important advantage as optical interconnects become more common in advanced computing hardware.
The message from SEMICON Taiwan 2026 is clear: co-packaged optics is not only changing chip design, it is also changing the way chips must be tested. To avoid costly failures and support large-scale adoption, the semiconductor industry is moving optical engine screening upstream, making mid-stage testing a key step in the next era of advanced packaging.
