8K capture at high frame rates, IP-based production, and remote (distributed) workflows are changing what broadcast networks have to deliver. More pixels, higher frame rates, and signals that travel between the venue, the outside-broadcast (OB) compound, and a central production facility put pressure on three things at once: bandwidth, timing accuracy, and end-to-end latency.
Hollow-core fiber (HCF) is one of the technologies being discussed for these demanding links. Because it guides light mostly through air rather than solid glass, it can lower propagation latency and reduce some optical impairments compared with conventional fiber. Below, we look at what hollow-core fiber is, how it affects latency, how it compares with standard single-mode fiber, where it realistically fits in broadcast networks, the limits that still apply, and what to check before specifying it.
What Is Hollow-Core Fiber?
In a conventional single-mode fiber, light travels through a solid core of doped silica glass. Hollow-core fiber inverts that idea: the signal is guided through a hollow channel - filled with air or an inert gas - that runs down the center of the fiber, surrounded by a finely structured glass cladding. Early designs used a photonic-bandgap structure; more recent designs, such as nested antiresonant nodeless fiber (NANF), have pushed performance much further.
The practical consequence is simple to state. In standard fiber, light spends its whole journey inside glass. In hollow-core fiber, it spends most of it in air. That single difference is what gives HCF its distinctive behavior in latency, dispersion, and nonlinearity. The concept has been developed over many years in academic and industrial research, including pioneering work on low-loss hollow-core designs at the University of Southampton. For a closer look at the structure and operating principle, see our overview of hollow-core fiber technology.
Why 8K Live Broadcast Needs Low-Latency Fiber
An uncompressed 8K signal is a large amount of data. At high frame rates the numbers climb quickly: uncompressed 8K at 120 frames per second can exceed 80 Gbit/s for a single feed, and redundant or multi-feed production multiplies that further. Even with light, visually lossless compression, a modern multi-camera 8K production moves very high aggregate bandwidth between the venue and the production facility.
Latency and timing matter just as much as raw capacity. In remote and distributed production, camera feeds, return video, talkback, and control data travel between the venue, the OB compound, the international broadcast centre (IBC), and central galleries. Operators need frame-accurate switching, tight multi-camera synchronization, and low round-trip delay so that talkback and return feeds stay usable. Much of this now runs over IP using the SMPTE ST 2110 suite of standards, which carries video, audio, and ancillary data as separate streams and depends on precise network timing (PTP).
It is worth being clear about where latency comes from. Glass-to-glass delay is the sum of many stages - capture, encoding and decoding, packetization, switching, synchronization, transport over fiber, and final display. Fiber propagation is only one of those stages. Hollow-core fiber can reduce the transport component; it cannot remove the latency contributed by encoders, switches, or displays.
How Hollow-Core Fiber Reduces Latency and Impairments
Light travels more slowly in glass than in air or vacuum. At telecom wavelengths the group index of silica is around 1.47, so a signal in standard single-mode fiber travels at roughly two-thirds of the speed of light in vacuum - adding close to 4.9 microseconds of delay per kilometre. In hollow-core fiber, where the light field sits mostly in air, the effective index is close to 1, and propagation delay drops to roughly 3.3 to 3.5 microseconds per kilometre.
In round terms, that is on the order of 30% lower propagation latency, or about 1.5 microseconds saved per kilometre of cable. Whether that matters depends entirely on distance. Over a long backhaul route it adds up; over a few hundred metres inside a venue it is negligible. Hollow-core fiber also tends to show lower chromatic dispersion and lower optical nonlinearity than solid-core fiber, because there is far less interaction between the light and the glass.
These are real, useful properties - but they are improvements, not magic. Hollow-core fiber reduces propagation latency and certain optical impairments in latency-sensitive links. It does not deliver "zero latency" or "zero distortion," and the benefit is proportional to the length and design of the link.
Hollow-Core Fiber vs Standard Single-Mode Fiber
The honest comparison is between a mature, low-cost, universally available technology and a fast-improving but still emerging one.
| Property | Standard single-mode fiber | Hollow-core fiber |
|---|---|---|
| Light-guiding medium | Solid silica glass core | Hollow air or gas core with microstructured cladding |
| Propagation latency | Baseline (about 4.9 µs/km) | Roughly 30% lower (about 3.3 to 3.5 µs/km) |
| Chromatic dispersion | Well characterized, managed with standard techniques | Typically lower |
| Nonlinearity | Higher (light confined in glass) | Lower (little light–glass interaction) |
| Attenuation | Low and consistent (about 0.2 dB/km class at 1550 nm) | Historically higher; recent NANF designs approach or, in research, rival standard fiber, but consistent low loss over long production lengths is still maturing |
| Splicing and connectors | Mature, widely supported | Specialized; ecosystem still developing |
| Deployment maturity | Decades of field experience, fully standardized | Emerging; limited field-proven track record |
| Cost and availability | Low cost, readily available | Premium cost, limited availability |
For most networks today, standard single-mode fiber remains the default, and where long-haul reach and low loss are the priority, ultra-low-loss G.654.E fiber is the proven choice. Standard single-mode fibers are defined by the ITU-T in recommendations such as G.652 and G.654, which is part of why the ecosystem around them - fibers, splicers, connectors, test equipment - is so well established. Hollow-core fiber is best understood as a complement for specific, latency-critical cases rather than a wholesale replacement. You can compare options across our single-mode fiber range, including ultra-low-loss G.654.E fiber for long-distance links.
Where Hollow-Core Fiber Could Fit in Broadcast and Beyond
Because its main advantages are latency and reduced nonlinearity, hollow-core fiber is most interesting where those properties are genuinely valuable:
- Latency-sensitive broadcast links, such as long venue-to-IBC routes or remote-production backhaul, where shaving propagation delay helps the overall timing budget.
- Data center interconnect, where low latency between facilities has direct operational value.
- Low-latency financial and trading networks, a frequently cited early use case.
- Time and frequency distribution, where consistent, low delay supports synchronization.
- Future 5G and 6G fronthaul and high-capacity transport, as the technology matures.
For the majority of current 8K productions, a well-engineered standard single-mode link - combined with ultra-low-loss fiber on the long spans, a clean IP architecture, and solid PTP timing - already meets the requirement. Hollow-core fiber earns its place in the smaller set of links where latency is the binding constraint or where future capacity headroom justifies early adoption.
Current Limitations Before Large-Scale Deployment
Hollow-core fiber is advancing quickly, but several practical factors keep large-scale broadcast deployment selective for now:
- Availability and supply. Commercial volumes are limited compared with standard fiber.
- Cost. HCF currently carries a price premium.
- Splicing and connectorization. Joining hollow-core fiber and terminating it reliably needs specialized techniques and tooling.
- Interoperability. Most existing plant is solid-core single-mode; mixing fiber types adds design and splicing complexity.
- Mechanical and environmental performance. Bend behavior, robustness, and long-term reliability under field conditions need validation for each design.
- Loss consistency over length. Achieving low, uniform attenuation across long production lengths is still maturing.
- Track record and standardization. There is limited long-term, field-proven history in live broadcast compared with established fiber types.
None of these are reasons to dismiss the technology - they are reasons to scope it carefully and to ask suppliers specific questions.
FAQ
Does hollow-core fiber really deliver zero latency?
No. It reduces propagation latency - on the order of 30%, or about 1.5 microseconds per kilometre, versus standard single-mode fiber. It does not eliminate latency. Total glass-to-glass delay also depends on encoding, switching, synchronization, and display, which hollow-core fiber does not change.
Is hollow-core fiber available for commercial broadcast projects today?
It is an emerging technology. Availability is limited and the supporting ecosystem (splicing, connectors, test equipment) is still developing, so standard single-mode fiber remains the default for the large majority of deployments.
How much latency can hollow-core fiber actually save?
Roughly 1.5 microseconds per kilometre, around 30% less propagation delay than standard fiber. The benefit scales with distance, so it is significant on long routes and negligible over short in-venue runs.
Can hollow-core fiber replace my existing single-mode network?
Not as a drop-in. Differences in splicing, connectorization, cost, and maturity mean it is usually introduced for specific latency-critical links rather than as a wholesale replacement for an installed single-mode plant.
What fiber do most 8K broadcast networks use today?
Standard single-mode fiber - typically G.652.D, with ultra-low-loss G.654.E on long spans - carrying IP-based production over SMPTE ST 2110.
Key Takeaways
Hollow-core fiber is a genuinely promising technology for the most latency-sensitive links in modern broadcast networks. By guiding light through air, it can cut propagation delay by around 30% and reduce dispersion and nonlinearity. Those are meaningful advantages over long, latency-critical routes - but they are improvements, not a leap to "zero latency," and large-scale broadcast deployment is still constrained by cost, availability, and ecosystem maturity. For most 8K productions, well-engineered single-mode links remain the practical choice; hollow-core fiber is worth evaluating where latency is the binding constraint. As always, the right decision comes from comparing specifications, test reports, and total cost - and from working with a supplier who can advise on fiber selection and, where needed, build to your requirements.