Written by Michael Zrihen, Senior Director of Marketing & Internal Operations Manager at Volico Data Centers.

Dark Potential: How Dark Fiber is Addressing Future Connectivity Needs

Unused optical fiber strands are lying dormant in underground conduits beneath cities and across continents, called dark fiber. Dark fiber has evolved from the status of a somewhat speculative asset to a critical infrastructure component.

Unlike lit fiber, where carriers control light transmission and bandwidth allocation, dark fiber provides raw capacity that can be “lit” on demand, when enterprises need to scale. Due to this latent potential, dark fiber connectivity is becoming an increasingly important element in enterprise infrastructures. The shift from using only lit fiber to planning long-term with dark fiber is driven by three converging demands: the explosive bandwidth requirements of AI, IoT devices, and cloud computing, the ultra-low latency needs of financial trading and industrial automation, and the growing imperative for secure, sovereign network control.

As enterprises increasingly take interconnection into their own hands, dark fiber is emerging as the foundation for next-generation digital infrastructures. This article explores dark fiber connectivity and how it is becoming essential for supporting future connectivity needs.

Privacy and Performance Benefits

Dark fiber’s superiority comes from its unique combination of physical properties and operational control. At the most basic level, these are unused fiber strands – but when properly deployed, dark fiber connectivity becomes the fastest, most flexible, and most private network medium available.

A bit of physics: light travels through fiber optic glass at about 200,000 kilometers per second. With dark fiber, this light path remains completely unobstructed – no carrier equipment adding microseconds of processing delay, no shared bandwidth with other users. This purity of transmission has two unbeatable advantages:

  • Deterministic latency: Financial firms achieve consistent 93μs Chicago-to-NYC transmission times
  • Bandwidth sovereignty: Hyperscalers can push 400G+ between data centers without carrier limitations

The technical magic happens through Dense Wavelength Division Multiplexing (DWDM). A single fiber pair can simultaneously carry:

  • 96+ individual light wavelengths
  • Each supports up to 1.6Tbps with modern coherent optics
  • All upgradable without replacing the physical fiber

This makes dark fiber connectivity uniquely future-proof. Wireless can hit spectrum walls fast, copper has physical limits, but fiber optics continue expanding and providing more and more potential for growth.

Manufacturers now deploy private 5G networks, achieving O-RAN’s demanding <250μs fronthaul requirements, while AI clusters use dark fiber’s massive throughput to synchronize distributed GPU training.

So, while the fiber itself is simple glass, the control it provides over light transmission creates networking possibilities that lit services simply can’t match. Dark fiber provides great strategic advantages in control and flexibility. Organizations can implement their own encryption standards, quality of service policies, and network architectures without carrier limitations. This control is particularly valuable for industries with stringent compliance requirements like healthcare, finance, and government operations.

Dark Fiber Connectivity Adoption Across Industries

Offering unparalleled performance, control, and scalability, dark fiber is transforming how industries approach connectivity. Let’s look at some of the key sectors using dark fiber connectivity to increase their performance.

Financial Services: Latency as a Competitive Edge

High-frequency trading (HFT) firms rely on dark fiber connectivity to minimize latency in electronic markets. On the critical Chicago-to-New York route (approximately 825 km), dark fiber delivers 8.1 ms round-trip latency, which is 1.4 ms faster than traditional lit networks.

In HFT, arbitrage opportunities last mere nanoseconds; this difference can translate to millions calculated in annual revenue. By deploying dedicated fiber routes, firms can eliminate unpredictable delays from carrier equipment, ensuring deterministic performance for algorithmic trading.

AI & Cloud Computing: The Need for Massive, Low-Latency Interconnects

AI training clusters and hyperscale cloud providers need two key attributes from their networks:

  • Extreme bandwidth (800G+ interconnects for GPU-to-GPU communication)
  • Sub-microsecond latency (for distributed training synchronization)

Dark fiber meets these needs where traditional WAN solutions fall short. Major cloud providers now build private dark fiber networks to bypass carrier backbones entirely, securing full control over traffic engineering and congestion management.

Telecom & 5G: The Backbone of Open RAN

The shift to Open RAN (O-RAN) architectures requires ultra-low-latency fronthaul links between distributed radio units (DUs) and centralized processing (CUs). Dark fiber provides:

  • <250 μs latency, meeting O-RAN’s strict timing requirements
  • Scalability for 5G densification (small cells, mmWave deployments)
  • Carrier-neutral flexibility, allowing operators to avoid vendor lock-in

Smart Cities: Reliable, Scalable Infrastructure

Smart cities throughout the world, like Barcelona, for example, use dark fiber connectivity as the backbone for large-scale IoT deployments, connecting:

  • 10,000+ sensors for traffic, air quality, and public safety
  • Municipal networks that avoid LTE congestion during peak events

Unlike wireless solutions, dark fiber ensures consistent, high-bandwidth connectivity without spectrum limitations—a necessity for real-time urban management.

The common thread across these use cases is deterministic performance. Dark fiber connectivity provides full control over network performance, eliminates congestion risks, and offers future-proof scalability. Whether the enterprise benefiting from it is a HFT firm trying to shave off milliseconds off trades, or one dealing with AI clusters synchronizing GPU workloads, or 5G networks meeting O-RAN latency specs, dark fiber connectivity makes it more efficient. For these organizations, the question is no longer whether dark fiber is worth it or not, but how they can integrate it into their infrastructure strategy.

What Is Deterministic Performance in Dark Fiber Networks?

Dark fiber connectivity provides deterministic network performance: predictable latency, guaranteed bandwidth, and stable transmission times, which are so critical for real-time applications.

In shared networks, congestion and carrier configurations can introduce variability. In contrast,  dark fiber offers granular control over the optical path itself. This allows organizations to precisely engineer every detail of the physical layer, from optimized amplification to low-dispersion routing.

Financial trading algorithms exploit this for nanosecond-precise computer-assisted trading, while healthcare systems rely on it for real-time imaging. Industrial automation and distributed AI training clusters also depend on deterministic sub-microsecond synchronization.

Dark Fiber Connectivity Costs

The financial case for dark fiber connectivity becomes compelling when looking at total cost of ownership. While the upfront costs of leasing fiber and lighting it can be substantial, organizations moving more than 10Gbps of traffic typically achieve 60% or greater savings over five years, compared to lit services.

But what’s more important is that dark fiber provides cost predictability, unaffected by bandwidth spikes or carrier pricing changes.

Let’s break it down: a hyperscaler moving 40Gbps of traffic would spend approximately 2.4 million annually on lit services at market rates. The same capacity on owned dark fiber, including lease costs and optical equipment, typically runs under 2.4 million annually on lit services at market rates. The same capacity on owned dark fiber, including lease costs and optical equipment, is typically under 1 million annually (after initial deployment). This economic model is particularly attractive for organizations with steady, growing traffic patterns that can amortize the initial investment over time.

Implementation Realities: Challenges and Solutions

Deploying dark fiber networks presents unique challenges that organizations have to navigate. Right-of-way acquisition remains a significant hurdle, with permitting processes in urban areas often taking 6-12 months. Neutral providers like Cologix and Zayo have built businesses around solving this problem, offering pre-positioned dark fiber in key interconnection hubs.

The last-mile activation process requires specialized expertise. Fusion splicing and optical testing can cost approximately $50,000 per mile, and they are particularly complex in dense urban environments. Providers are increasingly offering pre-terminated fiber solutions that reduce deployment complexity and cost.

The most significant challenge lies in skillset requirements. Designing and operating a dark fiber network demands expertise in optical engineering, DWDM provisioning, and network performance optimization, which many enterprises lack. This has led to the growth of managed dark fiber connectivity services, where providers handle the technical complexity while enterprises retain control over their traffic and architecture.

Emerging Technologies and Applications

As we look toward the future, dark fiber connectivity will enable several transformative technologies. Hollow-core fibers, currently in advanced trials, promise to reduce latency by 30% compared to traditional glass fibers by guiding light through air rather than solid glass. This could be revolutionary for financial trading and other ultra-low latency applications.

Quantum key distribution (QKD) networks will rely on dark fiber’s pristine light transmission properties to create theoretically unhackable communication channels. Several governments and financial institutions are already piloting QKD-secured dark fiber links for highly sensitive communications.

The edge computing revolution will be fundamentally enabled by dark fiber connectivity. As applications demand single-digit millisecond response times, computing resources must move closer to users. Dark fiber provides the deterministic, high-bandwidth connectivity needed to create distributed computing meshes while maintaining centralized management.

Conclusion

The transition to dark fiber connectivity represents more than just a technical evolution: it’s a fundamental shift in how organizations approach connectivity. In an era where performance, security, and control are paramount, dark fiber provides the foundation upon which next-generation applications will be built.

Enterprise dark fiber connectivity adoption is growing at a 23% compound annual rate, with no signs of slowing. Financial firms are achieving unprecedented trading speeds, hyperscalers are building global private networks, and cities are creating intelligent infrastructure – all powered by dark fiber. For technical leaders, the question is no longer whether to consider dark fiber, but how to integrate it into their connectivity strategy. In the coming decade, dark fiber will move from being a specialist’s tool to a fundamental component of enterprise infrastructure.

To learn more about dark fiber connectivity and the future of interconnection, visit: www.volico.com