Optical engines placed close to the switch ASIC on the same board, but not on the ASIC package itself.
What Is Near-Packaged Optics?
Near-packaged optics takes the core insight of co-packaging — shorten the electrical channel — without the manufacturing and serviceability difficulty of bonding optical engines to the ASIC substrate. The engines sit on the same printed circuit board, a few centimetres from the ASIC, with fibre carrying the signal from there to the faceplate.
What It Buys and What It Costs
The electrical channel is short enough that the SerDes can drive it with far less equalisation than a faceplate pluggable requires, which recovers a large part of the power saving. But the engine remains a distinct assembly that can be built, tested and in some designs replaced on its own.
The cost is that the channel is not as short as true co-packaging, so the saving is smaller. NPO is genuinely intermediate: better than pluggables, not as good as CPO, and considerably easier to build and service than either extreme suggests.
Why It Exists
Co-packaging demands an advanced packaging supply chain that not every switch programme wants to bet on. Bonding photonic dies to an ASIC substrate at yield is hard, and a programme that assumes it will be ready on schedule and is wrong has no fallback.
NPO is the hedge. The same silicon photonics engines, positioned so that the switch vendor is not committed to the packaging step. If CPO matures on time, the design migrates; if it slips, the product still ships.
Where You Meet It
In first-generation high-density designs, and in silicon photonics engine products aimed at switch builders rather than at operators. From a cabling standpoint nothing changes — the switch still terminates in fibre at the same reach classes.
Near-packaged optics
| Position | on the board beside the ASIC, not on its substrate |
|---|---|
| Electrical channel | a few centimetres |
| Power saving vs pluggable | large; below CPO |
| Optical engine | silicon photonics, usually a separate assembly |
| Serviceability | better than CPO — the engine can be a replaceable module |
| Supply chain risk | avoids the advanced ASIC-packaging step CPO needs |