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Deep|OFC 2026 Preview: 400G per Lane — The Next Major Inflection in Optical Interconnects
We have been steadfast supporters of Optics since a year and a half ago, publishing in-depth Optics reports almost every month. Regarding this OFC and future Optics technology trends, we have a lot to discuss — especially today, when there is so much debate and speculation.
The shift is not just about doubling speed from 200G → 400G per lane. It fundamentally reshapes the technology stack: modulation formats, photonic materials, and manufacturing capacity across the optical supply chain.
At 200G, IMDD dominates virtually all data-center interconnects due to its simplicity, low power, and cost advantages. But at 400G/lane, physics begins to push IMDD toward very high baud rates (~226 GBaud), making signal integrity increasingly difficult beyond short-reach links.
This creates a new architectural space: “Coherent Lite.”By adopting simplified coherent modulation (e.g., SP-16QAM) while avoiding the full complexity of telecom coherent systems, Coherent Lite targets the emerging 1–20 km campus / AI cluster interconnect regime.
In this middle distance range, coherent-lite architectures can achieve higher spectral efficiency with lower baud rates, improving signal robustness while keeping system cost manageable. This segment barely existed in the 200G era but could become a meaningful new optical market as AI clusters scale.
The shift to 400G also changes which photonic platforms matter.
InP EML remains the mature solution for IMDD
InP PIC becomes increasingly relevant for integrated coherent transmitters
SiPh offers scalable integration but faces performance limits for very high-speed modulation
TFLN emerges as a promising high-bandwidth modulator platform
One underappreciated implication: InP area demand explodes.As architectures move from single-channel IMDD lasers to large InP PICs integrating multiple active components, the InP die area per optical channel can increase by two orders of magnitude, dramatically increasing wafer demand.
In other words, a bandwidth upgrade at the system level may translate into a structural demand shock for the InP supply chain.
As AI infrastructure scales toward ever-larger clusters, optical interconnect architecture — and the photonic materials behind it — may become one of the defining bottlenecks of the next compute cycle. $LITE $COHR $AAOI $TSEM $AXTI
Detailed Report
fundaai.substack.com/p/deepofc-2026…
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