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

==== What they are doing together ====
* POET and NTT Innovative Devices are co-developing a 100G bidirectional optical engine using the Optical Interposer and NTT’s optical components, targeting AI-enabled mobile networking (front-/backhaul, etc.).
* The design aims for 4× higher bandwidth efficiency than current solutions (squeezing more Gbit/s through the same fiber resources). Stock Titan<ref>{{cite web|title=Stock Titan|url=https://www.poet-technologies.com/news/poet-technologies-partners-with-ntt-innovative-devices-on-next-gen-connectivity-solutions-to-support-ai-mobile-networking|publisher=Stock Titan|access-date=2025-11-10}}</ref>

Key interfaces:

: 

Why coupling efficiency is ''even more'' sensitive here
* Bidirectional means TX and RX share one fiber. Any loss in combining/splitting optics (WDMs, filters, couplers) eats directly into both directions’ budgets.
* You have more optical elements in the path (combiner/splitter, filters), so the link budget per interface is smaller; each coupling needs to be low-loss and stable.
* Mobile gear is often in tighter power and temperature envelopes than cloud data-centers.

So for NTT:
* Good coupling efficiency at each interface = → feasible 100G bi-di on real network fiber, → with realistic power consumption in radio or transport equipment.
* If POET’s passive alignment required, say, 1–2 dB extra per interface vs a finely tuned active design, the entire 4× “bandwidth efficiency” story could become fragile.

In other words, here coupling efficiency is a core enabler of the “do more over the same fiber” pitch, not a nice-to-have optimization.