co-Packaged Optics: The Future of Data Center Networking?
The relentless demand for bandwidth in modern data centers is driving innovation in optical networking. Co-packaged optics (CPO) has emerged as a leading contender to address these needs, but is it ready for prime time? This article dives deep into CPO, exploring its potential, challenges, key players, and how it stacks up against competing technologies like linear pluggable optics (LPO).
What is Co-Packaged Optics?
CPO fundamentally changes how optics and switching silicon interact.Instead of plugging optics into a switch, CPO integrates them directly onto the same silicon package. This proximity drastically reduces the electrical signaling distance, leading to significant gains in bandwidth, power efficiency, and perhaps, cost.
Think of it like this: currently, data travels a longer distance within the switch before reaching the optical connection. CPO shortens that journey, minimizing signal loss and maximizing speed.
Addressing the Reliability Concerns
One of the biggest hurdles for CPO is perceived reliability. The concern centers around the increased number of connections within the package – more points of potential failure. However, experts like Wilkinson at Lightwave Logic believe these fears are overblown.
“They shouldn’t fail that often. There are not a lot of moving parts in there,” he explains.While acknowledging the argument, he anticipates a smoother rollout than some predict, calling the failure concerns a “fallacy.”
Moreover, hyperscalers are already planning for potential issues. A simple,effective workaround is overbuilding capacity. As Karavalas suggests, adding 5-10% extra ports allows for quick swapping if an optic fails, ensuring uninterrupted service.
Who’s Investing in CPO?
The list of vendors actively developing CPO solutions is growing, though still relatively focused. Here’s a look at the major players:
* Broadcom: A frontrunner, Broadcom has been steadily advancing CPO since 2021. Their third-generation offering, the Tomahawk 6 – Davisson (TH6-Davisson), is currently shipping to early adopters. This Ethernet switch boasts a massive 102.4T bps of optically enabled switching capacity, developed in collaboration with Micas Networks, TSMC, HPE, and others.
* Nvidia: Nvidia announced new photonics switches in March 2025, also leveraging partnerships with TSMC. The Spectrum-X Photonics switches deliver up to 400T bps throughput, while the liquid-cooled quantum-X Photonics switches offer 144 ports of 800Gb/s InfiniBand, based on 200G bps SerDes. Shipping is expected “next year,” starting with the InfiniBand models.
* Cisco: Taking a more cautious approach, Cisco demonstrated a CPO switch in 2023 but hasn’t formally announced a product. Bill Gartner, SVP and GM of Cisco’s optical systems, highlights the challenges of achieving high yield and reliability with the 1,000+ optic connections within a CPO package. He emphasizes the industry will face a learning curve in this area.
CPO vs. Linear Pluggable Optics (LPO)
While CPO is gaining momentum, it’s not the only game in town. Arista Networks is championing a competing technology: linear pluggable optics (LPO).
Here’s a quick comparison:
| Feature | Co-Packaged Optics (CPO) | Linear Pluggable Optics (LPO) |
|---|---|---|
| Optic Location | Integrated directly onto switch silicon | Plugs into the switch |
| Distance | Very short electrical path | Longer electrical path |
| power Efficiency | Generally higher | Generally lower |
| Bandwidth Density | Higher | Lower |
| Complexity | Higher | Lower |
| Cost (Potential) | Lower (long-term) | Higher (potentially) |
Ultimately, the best solution will depend on your specific needs and priorities. CPO promises significant performance gains, but LPO offers a more established and potentially less risky path.
What Does This Mean for You?
If you’re building or upgrading
Worth a look