Editing Openai/69109937-2170-8005-9304-da49840bb5b9 (section)

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From POET’s ECOC 2023 slide deck on the Silicon Optical Interposer: ECOC<ref>{{cite web|title=ECOC|url=https://www.ecocexhibition.com/wp-content/uploads/POET-presentation-ECOC2023-RK-sharing.pdf|publisher=ecocexhibition.com|access-date=2025-11-10}}</ref>
* “Wafer scale assembly. Passive alignments.”
* “Passive Laser placement with high coupling efficiency”
* “Mirror finish etched facet technology – Lowest coupling loss in industry”
* “Low loss micro mirrors for out of plane coupling”
* “CMOS compatible low loss waveguides”

A recent primer (investor-oriented) describes: shareholdersunite.substack.com<ref>{{cite web|title=shareholdersunite.substack.com|url=https://shareholdersunite.substack.com/p/a-primer-on-poet-technologies|publisher=shareholdersunite.substack.com|access-date=2025-11-10}}</ref>
* Optical transmission loss under 0.2 dB/cm in their waveguides (that’s propagation, not coupling, but it tells you the internal waveguide stack is very low-loss).

In investor communications that circulated on Reddit, POET has been quoted with a specific figure: reddit.com<ref>{{cite web|title=reddit.com|url=https://www.reddit.com/r/POETTechnologiesInc/comments/pq39df/our_waveguides_are_2x_as_efficient_as_industry/|publisher=reddit.com|access-date=2025-11-10}}</ref>
* Vertical “out-of-plane” coupling ≈ 0.5 dB (i.e. ~89 % efficiency), and
* Claim that their waveguides are “2× as efficient as industry standard”.

Important caveats:
* These are company / investor claims, not peer-reviewed metrology papers.
* They refer to specific interfaces (e.g. micro-mirror or MMF/PD coupling), not the entire module’s total loss.

However, they are at least consistent with the ECOC slides that emphasize “lowest coupling loss in industry” and “high coupling efficiency” with purely passive laser placement. ECOC<ref>{{cite web|title=ECOC|url=https://www.ecocexhibition.com/wp-content/uploads/POET-presentation-ECOC2023-RK-sharing.pdf|publisher=ecocexhibition.com|access-date=2025-11-10}}</ref>

===== A vertical coupling loss of ~0.5 dB is ambitious but not insane for: =====
* Butt-coupling or mirror-based coupling with very good mode matching, and
* Short distances / controlled geometry on an interposer.

If their propagation loss is <0.2 dB/cm, then internal routing contributes almost nothing for the typical few-mm path lengths inside an engine. shareholdersunite.substack.com<ref>{{cite web|title=shareholdersunite.substack.com|url=https://shareholdersunite.substack.com/p/a-primer-on-poet-technologies|publisher=shareholdersunite.substack.com|access-date=2025-11-10}}</ref>

So you can plausibly end up with:
* Laser → interposer: maybe ~0.5–1.0 dB total (depending on interface and lensing)
* Interposer internal → very low
* Interposer → fiber: depends heavily on the module design, but if it’s via a lens array or further optics, that may be the bigger contributor — and in many architectures, that part is actually handled by the module partner, not POET itself.

We also know that POET’s engines are in commercial 400G/800G designs (FR4, DR8, etc.), and are qualified by large customers. lightwaveonline.com<ref>{{cite web|title=lightwaveonline.com|url=https://www.lightwaveonline.com/home/article/55270138/poet-technologies-poet-optical-interposer|publisher=lightwaveonline.com|access-date=2025-11-10}}</ref>
If their coupling were significantly worse than incumbents, the power budgets on those standards would simply not close.