Fiber-to-chip coupling covers the physical and optical structures that get light from an optical fiber into a photonic integrated circuit's waveguides, and back out again, including edge couplers, grating couplers and fiber-array attach mechanisms. It is patented separately from the PIC's core waveguide or modulator design because the coupling interface has its own alignment tolerances, materials and manufacturing steps that create independent, claimable inventions. In practice this dataset shows that separation clearly: the vast majority of records sit in optical-element IPC classes (G02B) that map specifically to connector and coupling structures, not to the semiconductor device classes that cover the PIC's active components.

Based on this dataset, yes. Filings rose from 40 in 2017 to a peak of 159 in 2022, then declined in every year since, down to 13 in the most recent partial year. Publication lag of roughly 18 months means the last one to two years are undercounted, but the decline starts well before that window, so the peak-then-decline shape is a genuine trend rather than an artefact of incomplete recent data. That points to a technology whose core coupling geometries have largely been claimed, with remaining activity concentrated in refinement rather than land-grab filing.

The recent-momentum data shows every tracked assignee — including large incumbents and specialist photonics firms — filing fewer patents in the latest year than the year before, with declines ranging from around 50% to 100%. No assignee in this set is currently accelerating its filing rate. That does not mean R&D has stopped; it more likely reflects publication lag combined with firms shifting inventive output toward adjacent, differently classified filings, or toward trade-secret protection for manufacturing know-how that does not show up in public patent filings.

US20240184067A1, assigned to SENTEA NV, claims a PCB-mounted photonic integrated circuit design where the board has an opening that thermally separates the region carrying the PIC and its fiber-attach interface from a second region, typically housing electronics. Anyone designing a PCB-integrated PIC package with a similar thermal-isolation opening should review this filing's specific claim language before finalizing a board layout, since the isolation mechanism — not just the general idea of separating hot and cool zones — is what is being claimed. Teams using different isolation approaches, such as separate substrates or active thermal management, are less likely to be affected.

The clearest gaps sit in branches that appear thinly against the dominant coupling-geometry claims: active alignment feedback systems for fiber arrays, thermal isolation techniques between PIC and fiber-attach regions, laser-source co-packaging with edge couplers, and wafer-level fiber array bonding. These areas show meaningfully fewer filings than core edge-coupler and fiber-attach geometry claims, which occupy most of the G02B-heavy filing volume. Any white-space claim should still be checked against the most-cited records in this set, since foundational patents in adjacent coupling structures sometimes extend into these thinner branches through broad dependent claims.