Research / Topics
Optics & Networking
How AI clusters are connected. Scale-up and scale-out networking, SerDes, AECs, pluggables, LPO and co-packaged optics.
19 posts
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2026
- NPO State of the Union
When NPO? Who NPO? Where NPO? Why NPO? Winners, losers, and more.
- 🎙️ PicoJool’s Al Yuen: The Case for GaAs VCSELs in Scale-Up Interconnects
GaAs VCSELs at 200G/lane, unconstrained supply vs. indium phosphide, the 8×200 / 16×100 / 32×50 flavors, WIN Semiconductors, the roadmap to 12.8T, and more
- Inside the 800G → 1.6T → 3.2T Race
Timing is everything. What the industry said about 800G, 1.6T, 3.2T in recent earnings calls
- VCSELs + 200G Wall In AI Datacenters?
Decades of short-reach dominance, the supply chain holding it up today, and the problems at the 200G transition
- Coherent's Vertical Integration Strategy
Coherent makes more of the optical stack in-house than any competitor. We walk through the business, the growth vectors, and whether breadth beats depth.
- GTC 2026 Keynote Debrief
Scale-up copper & optical, Groq, CPUs, tiered inference economics, SaaS is not dead
- Optics Primer, Part 3: Co-Packaged Optics (CPO)
From EML lasers and DSPs to silicon photonics and external CW lasers. How CPO works and the impact on the optical supply chain.
- Broadcom Makes Lasers?
Broadcom's InP fab, EMLs at 1.6T, full-stack CPO play, and comparing against Lumentum and Coherent
- Lumentum and the Laser Bottleneck
Lumentum is winning and still can't keep up. Coherent is closing in. Earnings, sell-side sentiment, and the tensions to track.
- Arista's Ethernet Bet
Q4 FY2025 earnings scored against the bull and bear cases
- Optics Primer, Part 2: LRO & LPO
LRO and LPO move signal processing out of the transceiver and into the switch, saving power at the cost of tighter system coupling. An incremental step toward co-packaged optics.
- Credo’s Reliability Thesis
Can Credo Reach Beyond AECs?
2025
- Optics Primer, Part 1: Traditional Pluggable Optics
Optical interconnects, pluggable transceivers, optical and electrical engines, DSP overhead, power and latency trade-offs
- GPU Networking, Part 4: Year End Wrap
Where Scale-Up, Scale-Out, and Scale-Across Stand at Year End 2025
- SerDes Matters!
What Is SerDes, Why It Matters, Which Companies Have SerDes Chops
- Credo AECs
Why Active Electrical Cables are a Billion Dollar Industry, and Why Credo is Dominant.
- GPU Networking Basics Part 3: Scale-Out
InfiniBand, UEC, Spectrum-X, Surprising Misconceptions
- GPU Networking Basics, Part 2
Front-End & Back-End, North-South & East-West Traffic, DeepSeek Example
- GPU Networking Basics, Part 1
Communication during Training, Scale Out, Scale Up, Network Architectures, Switches, etc.
