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Daily Missive

George Gilder: Led by Coherent, The Data Center is Turning to the Light

Loading ...Addison Wiggin

October 9, 2025 • 6 minute, 2 second read


data centers

George Gilder: Led by Coherent, The Data Center is Turning to the Light

“The introduction of optical fiber systems will revolutionize the communications network.”

– Charles K. Kao

October 9, 2025 — Hyperscale data centers buckle under the heat, weight, and waste of their hundreds and thousands of miles of copper connections linking together thousands of graphical processing units (GPUs).

Coming to the rescue is light in the form of optical connections, replacing copper in the nervous system of the AI data center.

As workloads scale, every additional GPU, accelerator, and memory module must move data faster, farther, and at the lower power and greater fidelity only optics can provide.

The company that already defines this transition is Coherent. Its leadership in optical transceivers — now shipping at 1.6 terabits per second — gives it a commanding position in the practical rollout of photonics across the modern data center. Coherent’s technology moves light across racks and rows where performance, power, and reliability converge at hyperscale.

The Physics Problem

Copper has long done this job, but the physics are starting to protest. Each new generation of AI chips pushes more data through the same metal traces, generating heat, distortion, and wasted energy. The signal boosters that keep copper alive add their own overhead, until the cost of moving bits begins to rival the cost of computing them.

Light sidesteps all of that. Photons travel cleanly through fiber, immune to electromagnetic noise, needing no re-timers or shielding. They carry more data, run cooler, and consume far less energy.

As shown in Table 1, the difference between electrical and optical interconnects is both physical and economic. Optical links deliver longer reach, greater bandwidth per lane, lower power per bit, and virtually no signal interference. These advantages compound as systems scale. Where copper struggles to sustain signal integrity beyond a meter or two, photonics can span entire racks with consistent performance. Power drops by multiples, latency shrinks, and thermal load plummets — translating directly into lower total cost of ownership.

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At hyperscale, those gaps turn into megawatts. Light isn’t just faster; it’s inevitable — the next medium for an intelligence that’s outgrown metal.

Coherent’s commanding lead in AI optics

Coherent’s fiscal-2025 results (ended June 20, 2025) show what inevitability looks like when it hits the income statement. Data center and communications revenue climbed 51% for the year, with AI datacenter sales up 61%.

Yet the company began shipping 1.6-terabit transceivers only in the fourth quarter, marking a new performance tier. Demand for modules below that level remains strong, and Coherent is already working on 3.2-terabit designs.

These are active transceivers — the small modules that sit at the edge of racks, converting electrical signals into light. They’re not fiber cables; they’re the engines that drive the link itself.

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Coherent 1.6T Optical Transceiver Module
Source: Coherent

Coherent has achieved scale production and qualification with nearly every major hyperscaler. Optical’s next step is to replace metal on a more micro scale aimed at chiplet or board-level integration. Startups including Ayar Labs, Lightmatter, and Celestial AI are developing experimental technologies to do this.

For now, however, Coherent is the one. It is already a multibillion-dollar public company serving global hyperscalers.

System-level optics has the economics

Inside a hyperscale rack, every watt counts. As shown in Table 2, moving from copper to optical links at the rack level sharply reduces total interconnect power, heat output, and lifetime cost. The example models a rack with thousands of 1.6 Tb/s links. By eliminating re-timers and minimizing signal loss, optics reduce power draw by roughly two-thirds and free up energy for additional GPUs within the same electrical envelope. These efficiencies translate into higher throughput per rack and lower cooling requirements, directly improving operating margins for hyperscalers.

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For hyperscalers, that difference translates directly into more GPUs per rack — more compute for the same electricity.

Coherent anchors the optical stack, now and to come

The startups mentioned here have been getting lots of publicity. But their work does not displace Coherent’s; it depends on it. If successful, each would add functionality closer to the chip — faster I/O, optical interposers, and photonic fabrics that will eventually draw from the same light sources and integration pipelines Coherent already supplies. Together, they would form an ecosystem where Coherent’s reliability and capacity make the startups’ ideas commercially viable.

Photonics in the data center is not a zero-sum race between veterans and startups. It is a layered transformation, where each company plays a distinct and necessary role. Coherent commands the outer layer — the one already generating revenue and scale. Its transceivers move light across racks, linking GPUs, switches, and servers with proven, manufacturable technology. That foundation is what allows the next generation of optical innovation to take shape.

Investors sometimes imagine that disruptive startups immediately unseat incumbents. In photonics, maturity is not a handicap — it’s a prerequisite. Coherent has the wafer fabs, module lines, and hyperscaler relationships to deliver real volume. The startups could extend the addressable market, but Coherent’s technology remains central to every architecture the company aims to build upon.

Coherent should not be seen as a transitional supplier but as the platform company around which photonic computing grows. As AI clusters demand more light at every layer — from rack to package — Coherent’s share of that energy pathway increases. The startups illustrate what’s possible; Coherent ensures it happens.

As light enters the data center — step by step, layer by layer — Coherent is the most experienced and scaled name in the field. It carries the light forward.

George Gilder
Grey Swan Investment Fraternity

P.S. from Addison: This is another of George’s recent essays, providing a nuanced look into the buildout of AI stocks, including why he believes the “Nvidia Model” is a passing phase in the movement toward the Age of Intelligence and the new technology he’s convinced is far superior to the limitations posed by microchips.

The fact that a technology is already in development that is advanced enough to disrupt this massive economy being built out to support AI data centers is reason enough to give George a listen. The replay of today’s Grey Swan Live! will be e-mailed to paid-up members tomorrow and, as usual, available in the archives on the Grey Swan website.

During the call, we whip through eight exponential technologies — AI, quantum computing, robotics, self-driving cars, blockchain, chips, advanced biotech, and even space — and why they are no longer advancing in isolation.

They’re colliding, compounding, and accelerating into what could be the single most extraordinary wealth-building event of our lifetimes, with or without a bubble in capex spending for datacenters on Wall Street.

The pace is staggering.

George just issued new research with our colleague Ian King, which you can review. Paid-up members can find a replay video of today’s Live! up on our site early tomorrow.

P.P.S. George is an amazing human being. At 87, he holds the #1 fastest pace for a 10k run in the above 85 category in the United States… and #2 in the world. He says he lost to a Mexican runner recently who, to his chagrin, lives and trains in thinner air at 9,000 feet.

If you’d like, you can drop your most pressing questions right here: Feedback@GreySwanFraternity.com. We’ll be sure to work them in during the conversation.


The New Law That Broke the Old Law

October 9, 2025 • Addison Wiggin

For decades, Moore’s Law — that the number of transistors on a chip doubles every two years — was the quiet metronome of progress. It defined an era. AI just smashed that clock.

Global data center spending will hit $900 billion by 2028, Kobeissi notes. AI servers are growing at a compound rate of +41%, with the overall market expanding +23%.

Just building the facilities, not including chips or servers, now costs $43 billion a year — up 322% in just four years. There are $40 billion worth of U.S. data centers under construction right now, up 400% since 2022.

For the first time in history, the total value of U.S. data centers under construction will soon exceed office buildings.

More than a metaphor, we’re living through a civilizational shift. The upside Grey Swan event, in our opinion, is that the narrative unfolds without any political interruptions or blowouts in the currency and credit markets. 

The New Law That Broke the Old Law
Speedrunning Rome

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Technology is a double-edged sword. We’re still living in the long tail of a hard money, capitalist society – and reaping new technologies out of it.

But the destruction of the purchasing power of the dollar stands to create a crisis – and drive investors back to safe havens like gold.

Speedrunning Rome
George Gilder: Intel: Sell the Rumors, Await the News

October 8, 2025 • Addison Wiggin

All these rumors could work out to Intel’s benefit. That’s something no investor can know. What we can know is that the road to recovery will be a rocky one, fraught with disappointments along the way. It is all but certain that at some point, Intel stock will once again be far cheaper than it is today. And at that later date, investors will have far more information to be able to judge the likely success of the promised comeback. We’re not going to buy the rumors. We will wait for the news.

George Gilder: Intel: Sell the Rumors, Await the News
Gold’s $4,000 Moment

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There’s something about big, round numbers that draws investors like moths to a flame.

In the stock market, every 1,000 points in the Dow or 100 points in the S&P 500 tends to act like a magnet.

Now, after consolidating for five months, gold has broken higher to $4,000.

Gold’s $4,000 Moment