Co-packaged optics (CPO) places optical transceiver components directly on or next to the switch or accelerator package substrate, rather than as a separate pluggable module at the faceplate. This shortens the electrical path between silicon and optics, which reduces power loss and enables higher data rates, and it is one of the main drivers behind the current wave of miniaturization patent filings. From a patent standpoint, CPO claims tend to sit across packaging, waveguide coupling and electrical interconnect simultaneously, so a single CPO patent can block work in several adjacent technical areas at once.

Filing in this corpus is spread across device manufacturers, telecom carriers and specialist optical interconnect firms rather than concentrated in one or two companies. The dataset shows a long tail of single-filing entrants alongside a smaller group of repeat filers, and several of the assignees with the longest filing histories show no filings in the most recent tracked year. Because publication lags actual filing by roughly 18 months, current rankings should be treated as a snapshot rather than a final scoreboard.

Filings rose steadily through the late 2010s, reached a midpoint of 39 in 2022, and peaked at 103 in 2024 before flattening rather than continuing to climb. This pattern is more consistent with a claim space that is filling in around established coupling and packaging architectures than with a market still in an early expansion phase. It does not mean R&D has stopped, only that the rate of new distinct claims being staked is no longer accelerating.

The IPC composition of this corpus is heavily weighted toward core optical elements and waveguide coupling (G02B), with far thinner coverage in printed-circuit-level integration (H05K) and multiplexing-aware compact architectures (H04J). That imbalance suggests the packaging, thermal management and system-level integration side of co-packaged optics has drawn fewer claims than the optical coupling mechanics themselves, making it a more open area for new filings. Waveguide-embedded package substrates and chiplet-to-optics electrical interconnect schemes stand out as specific under-claimed branches.

Citation counts inside any fixed-date patent corpus systematically favour older records, simply because they have had more years to accumulate citing references. In this dataset, the most-cited patents date to the 1990s and cover foundational optical module packaging, not recent co-packaged optics innovations. Use citation rank as a guide to which prior art a freedom-to-operate search must clear, not as a ranking of which recent technology is most important today.