As data rates soar in AI and hyperscale systems, copper interconnects are starting to buckle under the pressure. This blog post takes a closer look at co-packaged optics (CPO) and why putting optical engines right next to the ASIC—so fiber can exit straight from the substrate—could help cut losses, reduce retiming, and boost bandwidth-per-rack.
We’ll also touch on what needs to happen for CPO to really take off, who’s likely to jump in first, and how copper and optics might end up working together down the road.
Understanding the shift from copper to co-packaged optics
Copper traces and backplanes have done the job for decades, but as data rates go up, so do loss, jitter, and crosstalk. Shortening those electrical paths helps a bit, but it creates new headaches—think mechanical, thermal, and serviceability issues.
CPO puts optical engines right by the ASIC package, letting fiber exit directly from the substrate and making the electrical reach way shorter. In reality, this cuts down on the need for aggressive retiming and complicated encoding, while still keeping signals clean at high speeds.
Why co-packaged optics are being considered now
AI workloads and hyperscale density are pushing system architects to rethink things. They’re moving the conversion boundary from front-panel pluggables into the package itself, which keeps power and margins in check by bringing optics closer to the silicon. That means less wiring mess and lower energy per bit.
- Off-package lasers help with thermal and reliability headaches that come up when lasers sit too close to hot ASICs.
- With structured photonic tiles or optically enabled chips near the substrate, dense yet serviceable fiber-to-chip connections are finally realistic.
- High-demand workloads—where latency, bandwidth-per-rack, and power-per-bit really matter—will probably lead the way here.
How CPO reshapes system architecture
The CPO approach is more evolution than revolution. By moving optical conversion and transmission closer to the chip, designers can reclaim margin that used to get eaten up by long electrical paths and heavy equalization.
This changes how modules get packaged, how heat is handled, and even how maintenance works in crowded server racks.
Architectural implications in practice
- Optical engines land right next to the ASIC package, cutting interconnect length and latency.
- Fiber comes straight out of the substrate, so there’s less need for long, lossy copper traces.
- Packaging layers now include photonic tiles or optically enabled chips near the substrate for scalable data paths.
- Power and thermal design has to account for off-package lasers and the temperature quirks of photonic parts.
- This sets up a more modular route to higher bandwidths, with less reliance on long electrical signaling.
Challenges on the road to deployment
The benefits sound great, but there are still plenty of hurdles before CPO really takes off. Manufacturability and ecosystem readiness are big ones, especially since hyperscalers and AI infrastructure folks need to scale up specialized photonic assemblies fast.
Practical hurdles to scale
- Standardization and supply chain maturity for photonic tiles and integrated photonics.
- Reliability and long-term thermal management for lasers and photonics operating near dense ASICs.
- Yield, test, and repair procedures that can handle high-volume production without tanking performance.
- Compatibility with existing data-center ecosystems, software-defined infrastructure, and field service models.
The future landscape: a hybrid copper–optics path
The road ahead looks pretty hybrid. Copper’s not going anywhere for power delivery and short runs where its simplicity still wins out. But optics will take the lead where distance, density, and power constraints really bite—especially inside data-center racks and multi-chip modules.
The real aim? Push bandwidth closer to the silicon and unlock higher data rates, without sending energy-per-bit through the roof.
A pragmatic summary for researchers and practitioners
- Copper’s still essential for power delivery and short-reach interconnects.
- Co-packaged optics offers a scalable way to keep up with ever-higher speeds. It does this by cutting down electrical length and signaling overhead.
- Whether people adopt it depends on manufacturability, cost, and having a strong ecosystem for photonics integration.
Co-packaged optics feels like the next step in interconnect evolution. When you move the data-path closer to the silicon, system architects can push bandwidth and efficiency further.
But let’s be honest—making all this practical and reliable isn’t easy. The real winners? They’ll be the ones who figure out how to bring photonics, packaging, and software-defined infrastructure together and actually make CPO work at scale.
Here is the source article for this story: Optical connectivity moves closer to the chip