For years, fiber-optic innovation focused on sending more data through glass. The next breakthrough may come from removing the glass entirely.

Hollow Core Fiber (HCF) replaces the traditional solid glass core of optical fiber with an air-filled channel. This allows light to travel faster and reduces network latency by up to 30–35% per kilometer. With the growing demand for ultra-low-latency connectivity, this technology is gaining attention across the global telecommunications ecosystem.

As digital infrastructure advances to support artificial intelligence, cloud computing, and high-performance networks, latency in fiber-optic communication is becoming more critical than ever. Even microsecond-level improvements in signal transmission can significantly affect performance in latency-sensitive environments.

Hollow core fiber is emerging as a promising solution to these latency challenges, with the potential to enable new performance capabilities in next-generation networks.

What is Hollow Core Fiber?

Traditional optical fiber guides light through a solid glass core. Hollow core fiber replaces this solid core with an air-filled central channel which is surrounded by a precisely engineered glass structure.
Signals propagate faster through hollow core fiber, because light travels faster in air than in glass.

In practical terms, this means

• Conventional fiber latency: ^~ 5 µs/km
• Hollow core fiber latency: ~ 3.3–3.5 µs/km

This results in roughly 30–35% lower latency per kilometer.

In simple terms, hollow core fiber lets light travel mostly through air instead of glass, allowing data to move faster and reducing transmission delays.

Why Hollow Core Fiber Matters

Hollow core fiber is not intended to replace conventional single-mode fiber across all networks. Instead, it is emerging as a high-performance layer optimized for applications where low latency is critical.

Main advantages include:

Ultra-low latency: Signal propagation can be ~30–35% faster than in conventional fiber.

Reduced nonlinear effects: Signal distortions are greatly reduced because light travels mostly through air instead of glass. This allows stronger signals to be transmitted and can help extend how far data can travel without degradation.

Broader usable spectrum: Some hollow core fiber designs can support a wider range of wavelengths, allowing more data channels to be transmitted and potentially increasing overall network capacity.

Low attenuation demonstrations: Recent demonstrations have achieved extremely low signal loss, in some cases matching or even surpassing the performance of conventional fiber.

Enhanced security potential: The unique structure of hollow core fibers can make it easier to monitor the network and detect potential tampering or intrusions.

Hollow Core Fiber in Data Center and AI Infrastructure

While research and pilot deployments initially focused on metro and long-haul networks, hollow core fiber is now being increasingly explored for data center interconnect (DCI) and AI infrastructure.

AI systems often depend on large, distributed graphics processing unit (GPU) clusters that require extremely low latency communication to function efficiently. Reduced network latency enables distributed computing environments to operate with greater synchronization.

Due to these requirements, hollow core fiber is gaining attention as a potential high-performance optical layer for AI-driven data center connectivity.

Currently, these setups are mostly used to bridge data centers or connect massive campuses. In these environments, latency improvements can directly impact application performance.

Inside the data center, structured cabling environments are still largely based on traditional fiber technologies. However, as manufacturing capacity grows and connector ecosystems mature, hollow core fiber could become the new backbone for systems where every millisecond of speed is non-negotiable.

Key Developments in the HCF Ecosystem

The hollow core fiber ecosystem has grown significantly in the last few years, thanks to advancements made by telecom companies, research organizations, and producers of optical components.

Several organizations across the optical communications industry are advancing hollow core fiber technology and working toward scalable manufacturing. Ongoing research and industry trials aims to improve fiber designs, reduce attenuation, and increase achievable transmission distances. These advancements suggest that hollow core fiber is headed toward early commercial deployment in specialized network segments, going beyond laboratory demonstrations.

Market Outlook

Industry analyses suggest that the market for hollow-core fiber is anticipated to expand gradually in the next years due to a number of technological trends:

• Expansion of AI infrastructure
• Growth of cloud computing and hyperscale data centers
• Increasing deployment of 5G and future 6G transport networks
• Rising demand for low-latency financial and enterprise connectivity
• Continued investment in telecom infrastructure modernization

Due to the high demand for ultra-low-latency optical technologies, certain market projections indicate that the hollow-core fiber segment may reach over $2 billion by the end of the decade.

Challenges to Widespread Adoption

Hollow core fiber has a lot of potential, but the ecosystem is still developing.

Key challenges include:

• Higher cost compared with conventional single-mode fiber
• Specialized splicing and connectorization requirements
• Limited global manufacturing capacity
• Ongoing standardization efforts
• Integration complexity with existing fiber networks

Because of these factors, hollow core fiber is now best suited for high-value network routes where gains in latency yield quantifiable advantages.

Emerging Application Areas

Hollow core fiber is currently being investigated in a number of latency-sensitive fields:

AI and high-performance computing networks: Supporting distributed AI clusters and advanced compute environments.

Financial trading networks: Where microseconds can influence transaction outcomes.

Government and defense infrastructure: For secure, high-performance communications.

Advanced mobile transport networks: Supporting future time-sensitive networking requirements in 5G and beyond.

Long-haul optical systems: Where reduced nonlinear effects and broader spectrum use may offer performance advantages.

Looking Ahead

One of the most significant advances in optical transmission technology in recent decades is hollow core fiber. Rather than replacing conventional fiber, it is likely to complement existing fiber infrastructure by enabling ultra-low-latency connectivity in critical network segments.

As manufacturing capabilities expand and the broader ecosystem continues to mature, hollow core fiber may play an increasingly important role in supporting the next generation of digital infrastructure.

STL is actively developing HCF solutions for low-latency applications. The information provided here is based on publicly available information and data.

Sources

Microsoft Azure Networking Blog — Hollow Core Fiber Applications

University of Southampton Optoelectronics Research Centre publications on hollow-core fiber

Zion Market Research — Hollow Core Optical Fiber Market Report

Research & Markets — Global Hollow Core Fiber Market Report (2025)

Dataintelo — Hollow Core Fiber Market Forecast