POET and Marvell, truths and lies
As I received feedback, I promised I'd make this post regarding the Marvell incident.
First, I must say, this is my POV. I'm not a professional analyst, so make your own conclusions.
I will separate this into four blocks and a brief conclusion.
BLOCK 1. THE ORIGINS AND THE RESHAPE
Celestial AI was a company founded in 2020 that developed a systems architecture for light that is called Photonic Fabric. This took them years.
To prove this lights architecture concept, Celestial AI needed partners to validate their idea (because this was like a hypothetical highway of light).
There were more, but basically the chain was:
- Lasers (Lumentum/Sivers): Generate photons.
- Optical Engine (POET): Organizes and couples light to the system.
- Photonic IC (Imec/Celestial): Modulates light to transmit data.
- HBM Memory (Samsung): Stores the data flowing through the tissue.
- Control ASIC (Broadcom & TSMC): Manages all rack operations.
POET Technologies was key to validating the Photonic part. POET’s Optical Interposer solved the packaging nightmare by allowing lasers to be flip-chipped and aligned with high precision at a low cost. Without POET, Celestial AI would have struggled to build a prototype that was small enough and reliable enough to show to hyperscalers.
A major reason Celestial AI could claim their tech could work inside hot AI racks was POET’s Starlight engine. It allowed the lasers to be placed slightly away from the high-heat ASIC/GPU while still coupling the light efficiently. This separation was the proof that Photonic Fabric wouldn't melt in a real data center, this means, the technology would be manufacturable and thermally stable for AI data centers.
POET provided a plug-and-play light source. This allowed Celestial AI to focus entirely on their 16 Tbps modulation and routing architecture rather than spending years trying to become laser packaging experts themselves.
This is what the chain looks like after Marvell dumped POET and their adquisitions:
- Lasers (Lumentum/Sivers).
- Optical Engine (Marvell In-House): The 1.6T Light Engine that organizes and couples light into the system (replacing POET).
- Modulators (Polariton/Marvell): Ultra-fast plasmonic modulators that convert electrical signals to light at 3.2T speeds with minimal power.
- Photonic IC (Celestial AI/Marvell): The core Fabric architecture that manages optical data routing between chips and boards.
- HBM Memory (Samsung/ SK Hynix/ Micron).
- Control ASIC (Marvell Orion): The central brain (logic and switching) that orchestrates all rack operations and data traffic.
BLOCK 2. THE ISSUE
What's the deal here?
Marvell absorbed an IP (Celestial AI Photonic Fabric) that was proven to work with POET tech.
POET spent years working with Celestial AI to figure out exactly how the light needs to enter the Fabric (angles, power levels, thermal tolerances).
When Marvell bought Celestial AI, they bought all that joint research and contracts established between POET and Celestial AI. Marvell used POET as a free R&D lab to validate that the Fabric was commercially viable. Once Marvell saw the map, they realized they could try to build their own version by doing it themselves.
The NDA violation in April provided the perfect legal excuse to cancel the POET contracts without paying massive termination fees.
By dumping POET, Marvell was ripping a functional working system and replacing it with a different architecture yet to be proved.
Why? Because you can't just swap an interposer like a Lego brick. The original Photonic Fabric used POET's passive alignment and specific light-coupling angles.
Marvell is basically building a Photonic Fabric 2.0. Integrating their ecosystem. But Marvell is using a monolithic approach. This doesn't work with Photonic Fabric 1.0 (the original one).
By using Polariton’s plasmonic modulators, Marvell prints the light-handling parts directly onto the silicon at a much smaller scale. It doubles the speed (3.2T) while cutting the physical footprint.
Some analysts say the shift likely pushes full-scale production back by 12 to 18 months. This is why Marvell's 2026 updates focus on sampling and lab demos rather than the commercial shipping Celestial AI had originally promised for early 2026.
People don't realize Marvell is doing a big gamble. Marvell is betting that their plasmonic approach at the end of 2027-start of 2028 will be much better than the glass hybrid tech. They are sacrificing 2026-2027 revenue to try to own a big part of the future photonics pie.
(I assume that if you are a Marvel investor, you know what this means.)
Marvell didn't want to be dependent on a small company like POET, or the most critical component of their AI strategy (vertical integration) would collapse.
If you paid attention to the previous paragraphs, yes, you're right, plasmonics is an experimental tech. that has to work under a lot of heat and pressure (the solutions proposed are yet to be proved in the manufacturing stage).
Hyperscalers want reliable chips with thousands of hours of productive life cycle, Marvell won't be able to assure it in the short term regarding their photonics department.
POET Tech is proven. In 2026 other giants are doing another glass hybrid or mixed approach too.
Polariton’s Plasmonics is faster (3.2T), but it is much harder to manufacture at scale. It requires exotic materials (like specialized organic polymers) that aren't standard in silicon foundries.
BLOCK 3. THE RIGHT APPROACH?
Glass is a natural conductor of light. Silicon and plasmonics aren't.
Light travels through glass with almost zero resistance, it is a more efficient, natural medium for data. Plasmonics, which Marvell acquired through Polariton, forces light to interact with metal surfaces, which creates heat and signal loss.
By dumping the natural glass-based path of POET for the forced metallic path of Polariton, Marvell is making a massive high-risk bet, as I explained earlier.
The POET Way (Glass): Light stays in its natural state. It’s cool, stable, and proven. This is what allowed Celestial AI to validate the Fabric because it didn't overheat the chips.
The Marvell/Polariton Way (Plasmonics): It squeezes light into spaces smaller than its own wavelength using metal. This allows for 3.2T speeds in a tiny footprint, but it is fighting physics. The metal causes high insertion loss, meaning you need much more powerful lasers (Sivers/Lumentum) to punch the signal through.
POET's Interposer was built to be compatible with standard CMOS foundries.
Plasmonics requires integrating metals like gold or silver and specialized organic polymers directly onto high-end silicon.
This is a nightmare for mass production and can contaminate standard semiconductor lines. Marvell is betting they can solve a manufacturing problem that the rest of the industry has avoided for years.
By abandoning the POET/Celestial glass-based architecture, Marvell:
-Has to re-engineer the optical tissue to handle the heat and loss of the plasmonic modulators.
-Increasing Power Demand. Because plasmonics is lossy, the total system power might actually go up initially, potentially negating one of the original selling points of the Photonic Fabric.
Marvell’s leadership believes that silicon photonics (glass) will eventually hit a size wall. They are willing to break a working system today to try to be a company with a dominating system tomorrow based on Plasmonic.
4. PROS AND CONS
Pros
-Marvell's logic is that plasmonics allows them to squeeze light into spaces 100x smaller than glass allows (but take the 100x as a maybe, due to lasers/thermal management risks). Marvell is betting that glass is too big. They believe the future of AI is scale-in (everything inside one tiny chip), they think glass is simply too fat.
-While light moves fast in glass, modulating it (turning it on and off to create 1s and 0s) requires energy. To reach 3.2T or 6.4T speeds using glass, traditional modulators have to become very long (several millimeters) or use a lot of power to force the light to change.
-Plasmonics uses electrons on a metal surface, it can switch at terahertz speeds in a space of just a few microns. Marvell is betting that the energy they save in switching will make up for the energy they lose in friction (heat).
Cons
-Plasmonics generates localized hot spots on the chip because metal absorbs light. Glass stays cool.
-Plasmonic heat is a serious risk for the longevity of the chips in advanced stages. Energy efficiency is a huge con yet to be solved. Glass and solutions like POET tech promise a huge consumption reduction for the current generations.
-Worse conductor than light. Light and silicon simply aren't made to cooperate. It's a forced union.
-Contamination issues and organic polymers are yet to be tested in real loop cycles.
-If the glass becomes the standard, the big minds will find a way to reach higher speeds in a natural medium, they always do. Hybrid Bonding and 3D glass could be a more reasonable approach.
The industry is splitting right now. Which standard will prevail? Or will they be able to coexist?
CONCLUSIONS
I can be wrong, but when I see this case, I can't stop thinking about this.
I remember a part of the book Chip War. It said something like this:
Most people don't know, but a long time ago, near the 50s, the first transistors used germanium (Ge) instead of silicon (Si). Germanium was a faster medium to move electrons than Silicon. But, when the silicon approach took form, the germanium rapidly collapsed.
Why did silicon become the standard? Simple, the researchers discovered that silicon was a better medium (more stable and less susceptible to overheating) to move electrons than germanium.
The industry tends to prioritize stability and control over raw and unstable speed. I think Marvell is making the same mistake regarding the light. Time will tell.
Hope you enjoyed it.