MicroVCSELs vs MicroLEDs, a MicroExplainer

About this episode

Austin Lyons and Vik Sekar host a micro-explainer on the two competing micro-emitter technologies for AI interconnects: microLEDs and microVCSELs. They break down Credo's surprising pivot at OCP from its microLED acquisition to a microVCSEL product, revealing the core physics that give microVCSELs superior speed and reach. The episode establishes the technical reasons why the industry is converging on microVCSELs for the critical 5-50 meter gap in AI data centers. This episode is presented by Crusoe. Crusoe's Serverless Fine-Tuning trains an open model like Llama, DeepSeek, or GLM on your own data, and you pay per million tokens, not per GPU hour. About $2 buys roughly 5M training tokens on smaller models. Get $5 in credit to start: https://semidoped.com/crusoe Key Takeaways: - The new battleground for AI interconnects is the 5-50 meter "reach gap"—too long for copper cables limited to ~7 meters, but too short for expensive, supply-constrained InP long-reach optics. - MicroLEDs are limited by physics to ~3-5 Gbps over 5 meters. Their broad light spectrum causes "chromatic dispersion," smearing the signal and creating a hard ceiling on speed and reach. - To achieve high bandwid