Why Hollow-Core Fiber Is Suddenly Everywhere

Why it’s suddenly everywhere

1. 01

   On October 3 the Hubei provincial government announced that FiberHome had continuously drawn a 110.6 km antiresonant hollow-core fiber from a single preform — a Chinese manufacturing record that landed the term "hollow fiber" on Weibo’s hot search list within days.

2. 02

   Weeks earlier at the 2026 China Computing Power Conference, YOFC — the world’s largest fiber maker — said it had cut antiresonant hollow-core loss to 0.032 dB/km, the lowest transmission loss ever reported for any optical fiber.

3. 03

   China Mobile’s first commercial hollow-core line, opened in Guangdong in 2025, cut round-trip latency between the Shenzhen and Hong Kong stock exchanges to 1.07 milliseconds — catnip for high-frequency traders.

4. 04

   Microsoft, which bought hollow-core pioneer Lumenisity in 2022, is deploying 15,000 km of the fiber across Azure, while Chinese carriers plan more than 80,000 km across eight national computing hubs — an AI-era land grab for glass straws.

The timeline

1. 1991The photonic crystal idea

   Philip Russell at the University of Southampton proposes photonic crystal fibers — guiding light with microstructured holes instead of solid doped glass.

2. 2002Antiresonant guidance demonstrated

   Researchers show light can be trapped in an air core by surrounding it with thin glass tubes that reflect it back — but early fibers lose around 500 dB per kilometer, useless beyond the lab bench.

3. 2014Poletti’s nested design

   Southampton’s Francesco Poletti proposes the nested antiresonant nodeless fiber (NANF), tucking smaller tubes inside the ring of larger ones. Loss begins its long dive below solid glass.

4. 2022-12Microsoft buys in

   Microsoft acquires Lumenisity, a Southampton spin-out, to bring hollow-core fiber in-house for its cloud network.

5. 2024-11The 15,000 km pledge

   Microsoft says it will deploy 15,000 km of hollow-core fiber across Azure within 24 months to wire up AI data centers; AWS begins its own deployments.

6. 2025-08China’s first commercial line

   China Mobile lights a hollow-core link in Guangdong for Shenzhen–Hong Kong exchange traffic: under 0.09 dB/km loss, 1.07 ms cross-border latency.

7. 2026-090.032 dB/km

   YOFC announces the lowest fiber loss ever measured, roughly a fifth of the ~0.142 dB/km floor of conventional silica fiber, and says it has delivered over 10,000 core-kilometers.

8. 2026-10Manufacturing catches up

   FiberHome draws a 110.6 km continuous antiresonant fiber — proof the exotic structure can now be made at industrial lengths, and the story breaks out of trade press onto Weibo’s hot list.

The backstory

A fifty-year rule, broken by air

Every fiber-optic cable laid since the 1970s works the same way: light bounces down a hair-thin core of solid glass, kept inside by total internal reflection. The physics is elegant, but it comes with two taxes written into the glass itself. First, light in silica travels at about two-thirds of its speed in vacuum — a hard latency floor of roughly 5 microseconds per kilometer. Second, even the purest glass scatters and absorbs light, setting a loss floor near 0.142 dB/km that half a century of materials science could not cross.

Hollow-core fiber cheats by removing the glass from the light’s path. In the antiresonant designs that dominate today, a ring of thin-walled glass tubes surrounds an empty air channel; interference between reflections from those tube walls keeps the light confined to the air, where it travels at essentially vacuum speed. The payoff is roughly 30–47% lower latency per kilometer and — once the engineering matured — lower loss than any solid glass could offer. The idea took decades to tame: antiresonant fibers demonstrated around 2002 lost some 500 dB/km, and it was Poletti’s 2014 nested-tube geometry that finally pushed the numbers down toward, and then below, solid fiber. The loss curve has since dropped more than four orders of magnitude, eerily echoing the early improvement curve of silica fiber itself.

Why AI and money made it matter now

Laboratory records do not put a topic on Weibo’s hot search; money does. Two buyers arrived at once. The first was finance: in August 2025 China Mobile opened China’s first commercial antiresonant hollow-core line in Guangdong, purpose-built to shave latency on data shuttling between the Shenzhen and Hong Kong stock exchanges. Measured cross-border round trips fell to 1.07 milliseconds, with loss under 0.09 dB/km — at the time a record for any commercial fiber route. When microseconds price trades, a third less latency is not an upgrade; it is arbitrage — the same logic by which extreme-environment infrastructure unexpectedly serves basic science (see IceCube). That obsession with nanosecond-grade timing is also why the world just voted to abolish the leap second: a one-second clock glitch can void an entire trading day.

The second buyer was AI. Training clusters lash tens of thousands of accelerators together, and their interconnect can consume five to ten times more fiber than a conventional data center. Microsoft had already acquired hollow-core pioneer Lumenisity in December 2022; by November 2024 it was promising 15,000 km of hollow-core across Azure within two years, later enlisting Corning and Heraeus to scale production, and in 2025 its double-nested fiber with Southampton measured 0.091 dB/km — a result named one of Physics World’s breakthroughs of the year. China’s carriers moved in parallel: China Mobile’s Wang Dong says hollow-core unit prices fell more than 500-fold between 2023 and 2025 while single draw lengths grew from under a kilometer to 80 km, and China’s eight national computing hubs have planned more than 80,000 km of hollow-core deployment. That industrial backdrop also explains the frenzy in adjacent markets, from the AI memory supercycle to record fiber prices.

The September–October 2026 spike

The current wave of attention is a stack of records arriving in weeks. In June at MWC Shanghai, YOFC president Zhuang Dan reported cumulative deliveries above 10,000 core-kilometers, a best loss of 0.04 dB/km, and a longest single draw of 91.2 km. In September, at the China Computing Power Conference, the company cut that loss figure to 0.032 dB/km — a new world record, set against a backdrop of YOFC’s 888% jump in half-year profit as AI demand repriced the whole fiber industry. Days into October, FiberHome answered with the 110.6 km draw, attacking the technology’s other weak flank: manufacturability. Financial media framed it as China rewriting “a fifty-year iron law” of optical communications, and the phrase “hollow fiber” jumped from telecom journals to trending topics.

Key facts

Record loss

0.032 dB/km (YOFC)

Solid-fiber floor

~0.142 dB/km

Latency cut

30%+ vs solid fiber

First commercial line

China Mobile, 2025

SZ–HK round trip

1.07 ms

Price drop 2023–25

>500x

What people are saying

Common questions

Does hollow-core fiber speed up my home broadband?

Not directly, and not soon. The first deployments target places where microseconds or reach carry a price: exchange-to-exchange links, data-center interconnects, and computing-hub backbones. Your streaming video feels server and last-mile limits, not the glass in a backbone. The technology could eventually lower the cost and energy of the networks behind your connection — that is the realistic consumer benefit.

If it is better, why was it not used for fifty years?

Because making it is brutal. The guidance depends on sub-micron glass membranes arranged in nested tubes; early versions lost 500 dB/km and could only be drawn in short lengths. Loss fell below solid fiber only around 2022–2024, single draws passed 80–110 km only in 2025–2026, and prices fell 500-fold in just three years. Splicing hollow to solid fiber, standardizing structures, and surviving real-world installation remain active engineering problems.

Who is actually leading — China or the West?

Different halves of the race. The foundational designs came from the University of Southampton, and Microsoft is the largest Western buyer with its 15,000 km Azure plan. China leads on manufacturing scale and commercial routes: YOFC, FiberHome, Hengtong and ZTT supply all three national carriers, hold the current loss and draw-length records, and China Mobile chairs the ITU-T push to standardize the technology using Chinese drafts as the starting text.