# Hollow-Core Fiber: Technological Innovation Pioneering a New Trend in Optical Communications

Today, as computing power demand surges, 6G networks accelerate their deployment, and quantum communication reaches a critical inflection point, the physical limits of conventional solid-core optical fibers are increasingly becoming a bottleneck that constrains the development of the information society. When Microsoft’s team published in Nature Photonics a record‑breaking attenuation of 0.091 dB/km for hollow‑core optical fiber, this half‑century‑long “fiber revolution” reached a pivotal turning point: hollow‑core fibers, which use air as the transmission medium, are reshaping the global optical communications landscape with their disruptive technological advantages.

I. Breaking Physical Limits: From the “Glass Cage” to the “Light-Speed Tunnel”

Traditional quartz optical fibers guide light via total internal reflection, yet the glass medium introduces Rayleigh scattering, nonlinear effects, and dispersion—akin to imposing threefold constraints on the speed of light. Experimental data show that, over a 1,000‑kilometer transmission link, hollow-core fibers can reduce latency by 1.5 milliseconds compared with conventional fibers, translating into an advantage of tens of thousands of additional trades per second for high-frequency trading systems. Microsoft’s deployment of a 15,000‑kilometer hollow-core fiber network in its Azure data centers has boosted the efficiency of cross‑continent collaborative AI training by 40%, underscoring its pivotal role in ultra‑large‑scale AI clusters.

The more revolutionary breakthrough lies in a qualitative leap in transmission loss. In a 100‑kilometer‑scale experiment, China Telecom achieved a transmission rate of 37.6 Tbps, with losses reduced by 71% compared to conventional optical fiber—thanks to a hollow‑core structure that cuts the area of interaction between light and glass by 99%. As the optical signal travels through an air core just 12 microns in diameter, the level of interference it experiences is comparable to that of propagation in a vacuum. This physical isolation mechanism increases the fiber’s damage threshold by a factor of ten, opening up new avenues for high‑power laser transmission.

II. Reconstructing the Industrial Ecosystem: Bridging the Gap from the Lab to a Trillion-Dollar Market

On the cross-border financial dedicated line between Shenzhen and Hong Kong, China Mobile’s deployment of hollow-core fiber has reduced transaction latency to 0.98 milliseconds, a 32% improvement over traditional links. This latency optimization translates directly into economic benefits: according to estimates by a leading securities firm, every 1-millisecond reduction in latency can boost annualized returns by RMB 230 million. Driven by such value, operators worldwide are accelerating the commercial rollout of hollow-core fiber: China Unicom has completed the world’s first direct connection linking a submarine cable hub, a data center, and a financial center via hollow-core fiber, while China Mobile has launched China’s first commercially operational anti-resonant hollow-core fiber link in Guangdong. By 2025, the three major operators plan to procure more than 5,000 fiber‑kilometer‑equivalents.

The industrial landscape has been reshaped accordingly. Yangtze Optical Fibre and Cable Co., Ltd. has built the world’s first kilometer‑scale hollow‑core fiber production line, Hengtong Optic‑Electric has launched O‑band anti‑resonant hollow‑core fibers, and Zhongtian Technology has achieved a 31% reduction in latency at its AI‑powered computing center. These companies have established an innovation closed loop linking technology, applications, and standards, enabling China to account for 80% of global hollow‑core fiber capacity. More profoundly, this has driven an upgrade in industry value: although the unit price of hollow‑core fiber is 2,000 times that of conventional fiber, the high‑value use cases it supports—such as AI training and quantum communication—have boosted sector profit margins from 5% to 35%, giving rise to a high‑end optical communications market worth hundreds of billions of yuan.

III. Unveiling the Vision of the Future: From the Communications Revolution to a Civilizational Leap

In the field of quantum communication, China Telecom has successfully conducted a hundred-kilometer‑scale quantum–classical co‑fiber transmission experiment, resolving the longstanding challenge of quantum states being easily disrupted by classical signals in conventional optical fibers. The low‑noise characteristics of hollow‑core fibers have extended the range of quantum key distribution beyond 300 kilometers, laying the groundwork for building a global quantum‑secure network. This technological convergence is giving rise to a new paradigm—the quantum internet—which will redefine the operating principles of critical sectors such as information security, financial transactions, and government communications.

Industrial applications are likewise undergoing a transformation. In laser processing, GW‑level high‑power lasers transmitted through hollow‑core fibers have tripled the cutting speed of automotive sheet metal; in the medical field, 10.6‑micron far‑infrared lasers delivered via such fibers enable precise subcutaneous surgery up to 10 centimeters deep; and in the energy sector, ultra‑long‑distance (300‑kilometer) power‑transmission relay protection systems leveraging hollow‑core fibers achieve response times on the order of 10 milliseconds, ensuring the safe operation of ultra‑high‑voltage grids. These applications underscore the universal value of hollow‑core fibers as a foundational infrastructure for optical transmission.

IV. Challenges and Opportunities: The Technological Long March Toward the Future

Despite its promising prospects, the large-scale deployment of hollow-core fibers still faces three major challenges: first, manufacturing complexity grows exponentially, requiring micron‑level precision to control a nested structure of hundreds of glass tubes; second, splice loss can reach as high as 0.5 dB per splice—ten times that of conventional optical fibers—necessitating the development of specialized splicing equipment; and third, the absence of industry standards results in poor equipment compatibility, with no unified technical roadmap yet established worldwide.

However, historical experience shows that technological cost reductions follow a “Moore’s Law–style” trajectory. With Yangtze Optical Fibre achieving kilometer‑scale continuous drawing and Zhongtian Technology mastering low‑loss splicing, the cost of hollow‑core optical fiber is declining at an annual rate of 30%. Experts predict that by 2028 its unit price will fall to one‑tenth that of conventional optical fiber, triggering a large‑scale substitution effect. Even more promising is the prospect that, once hollow‑core fibers are deeply integrated with silicon photonics chips and photonic integrated circuits, they could give rise to integrated photonic engines a hundred times smaller than today’s optical modules, fundamentally reshaping the architecture of computing infrastructure.

Standing at the historical juncture of 2026 and looking back, from Charles K. Kao’s groundbreaking proposal for fiber‑optic communication in 1966 to today’s breakthroughs in hollow‑core fibers that push the boundaries of physics, this 60‑year technological marathon has entered its final sprint. As light races through hollow‑core fibers at speeds approaching that of a vacuum, it carries not only data and energy but also the hope of propelling human civilization into the age of intelligence. This communications revolution, sparked by air itself, will ultimately reshape how we perceive the world and connect everything.