UV Curing for Co-Packaged Optics (CPO): The 2026 Manufacturing Guide
Co-packaged optics demands the tightest fiber-bonding tolerances in commercial photonics. Here is how UV curing controls sub-100 nm alignment as the CPO market scales rapidly through the end of the decade.
Co-packaged optics (CPO) is reshaping how AI data centers move data. By integrating optical engines directly onto the same package substrate as the switch ASIC or accelerator, CPO removes the electrical bottleneck that has limited bandwidth for a decade. But it also introduces the most demanding fiber-bonding tolerance of any commercial photonics application — and UV curing sits at the heart of that challenge.
Why CPO changes the bonding game
In a traditional pluggable transceiver, the optical engine tolerates alignment shifts of a few hundred nanometers. CPO does not. Silicon photonic engines must be bonded to fiber array units (FAUs) at an alignment stability of 50–100 nanometers, and that alignment must survive 10,000+ thermal cycles between −40 °C and +125 °C over the product's life.
The dominant failure mode is deceptively simple: UV adhesive cure shrinkage. If the adhesive contracts unevenly as it cures, the fiber shifts — and even a 100 nm shift degrades optical coupling efficiency enough to fail the part. Controlling that shrinkage means controlling the UV dose delivered to every single bond site.
The three requirements CPO places on a UV system
- Dose repeatability. Every bond must receive the same UV energy, cycle after cycle, so cure shrinkage is consistent and predictable.
- In-process verification. At sub-100 nm tolerances, you cannot trust an open-loop lamp. Dose must be measured at each bond site.
- Throughput. As hyperscalers commit to CPO switch architectures, cure cycles must stay under ~5 seconds per bond site to support production economics.
How OmniCure addresses each one
The OmniCure LX500 multi-channel UV LED platform, paired with 365 nm V3 LED heads, delivers the high-stability, multi-point curing CPO fiber-array bonding requires. Combined with in-process radiometry, manufacturers can verify UV dose at each individual bond site — establishing the process-control discipline that a 50–100 nm budget demands.
For qualification lots and new product introduction — where documented stability matters most — the OmniCure S2000 Elite's Closed-Loop Feedback holds output within ±5% of set point across millions of cycles, with NIST-traceable calibration.
The lesson from high-volume photonics: alignment is won or lost in the cure. Repeatable dose is not a nice-to-have — it is the process.
The market context
The CPO market is one of the fastest-growing segments in commercial photonics, expanding rapidly as the industry shifts from pluggables to CPO and from copper to optics. At GTC 2025, NVIDIA unveiled silicon-photonics switch platforms using CPO to connect GPUs at 1.6 Tbps per port, with Broadcom, Cisco, Intel and Marvell pursuing parallel architectures. Every one of those packages depends on precision UV-cured fiber bonding.
Where to go next
- See the full Co-Packaged Optics case study for the process detail and recommended systems.
- Compare UV curing systems across spot, area, and LED platforms.
- Have a specific CPO bonding step to validate? Talk to our engineers.
ETIA is an authorized OmniCure distributor in Thailand and Vietnam, and also supplies Phoseon, Fusion UV and Noblelight UV curing systems.
Have a UV curing challenge?
Our engineers match the right system to your exact process — from selection to validation.