Sivers’ pending DFB yield patent (WO2026078399A1) — per-laser on-wafer testing with custom cavity corrections
I saw this on X and it’s worth a proper look: Sivers Photonics has a pending WIPO patent application, WO2026078399A1, “Distributed feedback laser modification,” filed October 2025 and published April 2026.
The problem it attacks is specific and real. In DFB manufacturing, variation in the optical phase at the laser cavity facets causes threshold gain spectrum variation, which degrades single-mode operation. Lasers that fail the single-mode parametric tests or land out of spec are yield loss — scrap.
The existing fix is post-test laser trimming or cutting: slow, serial, specialized equipment. One laser at a time.
Sivers’ approach: test each laser while it’s still on the wafer (probe card, segmented contacts), compute a customized correction per device, then apply all those different corrections in wafer-level lithography steps — patterning, deposition, implantation, etching — concurrently across the wafer. The corrections tune each cavity nonuniformly (refractive index, carrier injection, or stress distribution, axially or across the cavity) to compensate for that device’s measured variation. Then re-test.
Why it matters: Glasgow is being prepped for 100M+ CW DFB lasers a year. At that scale the economics are set by usable yield, not wafer starts. This is IP around making high-volume DFB production more efficient and predictable — sellable capacity without extra capex.
Caveats, since they matter here:
Net: it’s a real signal they’re engineering for yield at volume, not just adding capacity. That’s the right problem to be solving ahead of the AI datacenter ramps.
Credit to Pep_Invest (@Pep_Invest) for digging this one up: https://x.com/Pep_Invest/status/2107065762233950677
Patent: https://patents.google.com/patent/WO2026078399A1/en
TL;DR: Sivers has a pending patent on testing each DFB laser on-wafer and applying custom per-device cavity corrections via lithography. It targets facet-phase yield loss — the scrap driver in DFB manufacturing. No yield figures in the filing, not granted yet, and most likely defensive IP for Glasgow’s 100M+/year ramp.