“Markets react to earnings calls.
Physics doesn’t.”
About PhotonCap
PhotonCap is an independent photonics and semiconductor research platform. It covers silicon photonics, CPO, semiconductors, AI, and adjacent technologies, all interpreted through the lens of optics.
As power efficiency and bandwidth limitations become the primary bottleneck for AI infrastructure, photonics is no longer optional. PhotonCap analyzes the technical realities behind that transition.
Why Subscribe
Most photonics coverage falls into two categories: too shallow for engineers, or too technical for investors. PhotonCap is built for people who need both.
This is not just a place to learn about technology. It connects specific photonics constraints to real business outcomes. Why a packaging limitation or a particular wafer bottlenecks an entire product roadmap. Why a specific component matters for a company’s margin structure. Earnings calls analyzed from an optics perspective, identifying what the physics says is right and what it says is wrong.
Written to be accessible even without a technical background. Every post goes through dozens of rounds of self-review before publication.
Browse the archive and decide for yourself: https://photoncap.substack.com/archive
About Me
Ph.D. in Electrical Engineering, specializing in photonics. Currently working in the photonics industry in Silicon Valley. Over a decade of experience in optics/photonics research and engineering at national research institutes and UC Berkeley, including hands-on work across silicon photonics (standard CMOS runs on SOI wafers, SiN platforms), photonic integrated circuit design, device characterization, and optics-related advanced packaging. Korean government scholarship recipient throughout undergraduate, master’s, and doctoral studies. Recipient of a Korean Ministry of Education Global Ph.D. Fellowship (~$90K over 3 years) for research in photonic devices and packaging. 13 patents filed/granted in photonics. 9 publications in peer-reviewed journals including Nature, IEEE, and OPTICA. 10+ presentations at international conferences, including an invited keynote.
I run PhotonCap independently alongside my day job. There is no team, no editor. Just original research I would want to read myself.
There are many places that summarize press releases. An independent research platform run by someone who has personally designed, fabricated, and characterized photonic devices is rare anywhere in the world.
What Subscribers Are Saying
“Found you like a person who can compete with Citrini.”
“Nice technical depth, and independent analysis. Happy to support your work!”
“Hey PhotonCap, you do great work and I have gained a lot from reading your articles. I’m more than happy to subscribe so that you can continue your excellent work.”
“I subscribed as a founding member because I have seen your work and you do an excellent job! I am a hedge fund manager and have a substantial interest in many of the names you cover. I have owned **** at some level since 2016. It is now my largest position. I own ****, ****, ****, ****, & ****, plus **** & ****. Thanks for your coverage”
“Great analysis, keep in touch.”
“Thank you for your incredible work! I’m a college student who only recently discovered the fascinating world of semiconductor technology, and your content has been both incredibly educational and genuinely captivating.”
“Photonics is another technology that will provide an alternative to copper”
“loved your post on twitter about NVDA and AVGO for copper in contrast to optics. big reason why i am subbing, keep up the great work!”
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“I’m trying to understand the semiconductor space as it appears to provide investment opportunities and his Substack appears to provide valuable information.”
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“I studied materials science engineering and do investments now. Appreciate the technical explanations and the stock implications. “
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“Learnt from articles “
What You Get
PC101 Lecture Series. A structured, ground-up education in photonics fundamentals. From how silicon photonics chips are made, to fiber-to-chip coupling, to CPO packaging. Built for investors and engineers who want to understand the technology, not just the ticker symbols.
Company & Technology Deep Dives. Original analysis on individual companies and technologies across the photonics value chain: silicon photonics, coherent optics, optical circuit switching, transceiver supply chains, and more.
Earnings Through a Photonics Lens. When companies report, most analysts focus on revenue beats and margin trends. PhotonCap focuses on what the physics actually implies for the forward outlook.
Conference Paper Analysis. Breaking down key papers from OFC, SPIE, IEEE, and other major photonics conferences into actionable insights.
Who Reads This
Professionals across quantitative hedge funds, institutional investors, sell-side research teams, and semiconductor industry practitioners currently subscribe. The publication reached #1 on Substack’s Rising Bestsellers in Technology within five weeks of launching paid subscriptions and #4 on New Bestsellers (4/1/2026).
As of 4/1/2026, PhotonCap also runs a 32,600+ follower presence on X (@PhotonCap) and operates the [PIC] community, a 1,500+ member community dedicated to photonic integrated circuits and the broader photonics ecosystem.
This is a technology education and research platform. It is not financial advice.
