What is Dark Fiber?

The Background of Dark Fiber Birth

In the 1980s and 1990s, the communication field experienced a huge transformation. With the rise of the internet and the rapid development of communication technology, telecom companies invested in underground fiber optic cable networks. Their strategy was often to dig and bury more fiber than what was needed at the time. The idea behind this practice was that if most of the costs associated with underground fiber installation were due to the labor, equipment, and operations required to lay the cables (rather than the cables themselves), then it made sense to install extra cables to save money because they would be in place when more cables were needed for communication and data transmission capacity in the future.

The 1980s and 1990s were the golden age of fiber optic communication. Traditional copper wire cables were gradually replaced by fiber optics because fiber optics offered higher bandwidth and longer transmission distances. Compared to copper wires, fiber optics transmitted data faster and were less susceptible to electromagnetic interference. This made fiber optics the ideal choice for communication networks at the time. However, the installation and maintenance costs of fiber optics were relatively high. Therefore, to reduce costs and prepare for future demand, communication companies usually adopt an overbuilding strategy.

The Concept of Dark Fiber

The core of dark fiber is the transmission of optical signals. Unlike traditional telecom networks, it does not use electrical signals but uses optical signals to communicate through fiber optics. This optical signal transmission is based on the physical characteristics of light, which has the advantages of high speed, high bandwidth, and low latency. Light is a form of electromagnetic wave, which has the following features:

• Fast speed: The speed of light in a vacuum is about 300,000 kilometers per second, much faster than the speed of electrical signals in cables.
• High frequency: Light waves have a higher frequency, which enables them to carry large amounts of data.
• Immune to electromagnetic interference: Optical signals are not affected by electromagnetic interference, thus the communication quality is more stable.

Optical signal transmission is done by emitting laser beams and guiding them into fiber optics. Fiber optics are a kind of light-guiding medium composed of ultra-thin glass fibers, usually with a two-layer structure: core and cladding. The core is the main area for optical signal transmission, whose refractive index is higher than that of the cladding, which makes the optical signal completely reflected by the core and not leak out. This principle of total internal reflection enables optical signals to travel hundreds or even thousands of kilometers in fiber optics without attenuation.

Optical signals can be encoded in different modes, usually using the brightness (intensity) or phase (waveform shape) of light to represent data. This encoding usually uses modulation techniques, such as amplitude modulation (AM) or frequency modulation (FM), to convert digital data into optical signals. Different encoding methods can achieve different data transmission rates and bandwidths.

The term “dark fiber” refers to fiber optic cables that have been installed underground but have not been activated or utilized. These cables are called “dark” because they have no data transmission activity. In these cables, optical signals are not lit up, so they are in a “dark” state. One of the main advantages of this strategy is that the physical cost of installing fiber optic cables is one-time. Once the cables are buried underground, future activation and utilization only require relatively low costs. This provides flexibility for communication companies to expand network capacity as needed.

The Demand Drivers of the Dark Fiber Market

Increased Video Streaming Demand

With the surge of internet video content, users’ demand for high-quality, seamless video streaming experience is also increasing. The popularity of online video platforms, streaming services and remote conferencing applications has led to rapid growth of video traffic. This poses a great challenge to traditional internet connections, as they may not be able to meet the requirements of high bandwidth and low latency.

Dark fiber becomes the ideal choice to meet the video streaming demand, by providing high-bandwidth and low-latency connections. Enterprises and service providers can leverage dark fiber to support HD, 4K and even 8K video content transmission, while ensuring users enjoy an excellent viewing experience.

Cloud Computing and Data Network Activities

Cloud computing and data network activities have a profound impact on enterprise and individual users. As more and more data and applications migrate to the cloud, the requirements for network connections also increase. Enterprises need to be able to access cloud services quickly and reliably, to support their daily operations and data storage needs. Dark fiber provides high-capacity, low-latency connections that can meet the needs of cloud computing and data network activities. It enables enterprises to transfer large amounts of data to the cloud quickly, while maintaining high reliability and security.

Hyperscale Data Centers and Cloud Services

With the rise of cloud computing, the number and size of hyperscale data centers and cloud service providers are also increasing. These data centers need a lot of high-speed connections, to support their internal data transfer and communication with customers. Traditional internet connections may not be able to meet these requirements.

Dark fiber provides an ideal solution for hyperscale data centers and cloud services. It can provide high-capacity, low-latency connections, to support data replication, backup and recovery operations between data centers. In addition, dark fiber also allows data center providers to scale flexibly according to customer demand, providing users with excellent performance.

Increasing Number of IoT Devices

The Internet of Things (IoT) is one of the key technology trends that connects the world. More and more devices, from smart home devices to industrial sensors, are connected to the internet, to enable data collection and remote control. The explosive growth of these devices leads to the demand for more network connections.

Dark fiber provides a reliable, high-capacity connection option for IoT. It can support large-scale sensor networks and IoT devices, while maintaining fast data transmission and low latency.

Supporting 5G Cellular Tower Backhaul

The introduction of 5G technology will bring faster mobile data speeds and lower latency. To achieve the performance potential of 5G networks, a large number of high-capacity fiber optic connections are needed. These connections are used to transport cellular signals from cellular towers back to the core network, for processing data traffic.

Dark fiber serves as a key component to support 5G networks, by providing sufficient bandwidth and reliability, to meet the demand for high-speed data transmission. It can be used to connect cellular towers and core networks, ensuring high performance of 5G networks.

Small Cells and Distributed Antenna Systems (DAS)

New wireless network infrastructure, such as small cells and distributed antenna systems (DAS), are also driving the demand for the dark fiber market. These systems aim to provide wider coverage and better wireless connections, to meet the growing mobile communication demand. To support these new wireless networks, reliable fiber optic connections are needed. Small cell systems are usually deployed in urban areas, to provide denser coverage, while distributed antenna systems bring signals into buildings and other hard-to-reach areas. These systems require fast, stable fiber optic connections, to ensure high-quality transmission of wireless signals.

The Use Cases of Dark Fiber

High Bandwidth Demand

If your bandwidth demand is high and growing, dark fiber may be your ideal choice. Traditional ISP connections usually offer limited bandwidth, which may not meet the needs of large enterprises or organizations. However, as businesses expand and undergo digital transformation, the demand for more bandwidth becomes increasingly urgent.

1. Bandwidth demand over 1 Gbps: If your bandwidth demand has exceeded 1 Gbps, traditional ISP connection options may become expensive and inflexible. In this case, dark fiber may be more cost-competitive than traditional internet connections. Once you install dark fiber, you can easily scale up your bandwidth as needed, without requiring major infrastructure changes.

2. Rapid growth: Most companies’ bandwidth demand grows at a double-digit rate every year. In this situation, the economic benefits of dark fiber will become more evident over time. In contrast, traditional ISP connections may not be able to keep up with this growth rate, as they usually require complex negotiations and upgrades with the providers.

Building Private, Highly Customized Networks

In some dedicated network use cases, dark fiber can achieve better results than any other connection option. Here are some situations that are suitable for using dark fiber:

1. Low-latency trading networks: Financial institutions and exchanges need extremely low latency to execute high-speed trades. Dark fiber can provide lower latency than standard ISP connections, ensuring fast execution of trades.

2. Data center links: Data centers need high-bandwidth and low-latency connections, to support fast data transfer and cloud computing workloads. With dark fiber, you can build highly customized data center links that meet your needs.

3. Security requirements: In some cases, security is critical. Using dark fiber, you can have full control over the security of your network, ensuring data transmission is protected from external interference.

Standard WAN Use Cases

Besides highly customized network needs, many enterprises still need to meet standard WAN use cases. In these situations, dark fiber can also be an attractive, future-oriented option.

1. Connecting two buildings: If you need to connect two buildings with a high-bandwidth connection, dark fiber can provide a high-performance connection option. This is especially appealing for enterprises that span large urban areas.

2. Data center links: High-bandwidth connections between data centers are essential for cloud computing, backup and disaster recovery. Dark fiber can provide reliable data center links, ensuring fast data transfer.

3. Regional competition impact: The price of dark fiber may vary greatly depending on regional competition. If you are located in a major metropolitan area with a lot of fiber, dark fiber may be a more attractive option, replacing the wave circuits or other point-to-point fiber options that you normally use.

The Classification of Dark Fiber

Dark fiber can be divided into two main categories: metropolitan fiber and long-haul fiber, which differ in their coverage, structure, and purpose.

Metropolitan Fiber

Location and Coverage

Metropolitan fiber is a type of fiber optic network that mainly distributes within cities, covering densely populated, high-traffic locations. Its goal is to bring high-speed fiber connections to the doorstep of enterprises. The key feature of this fiber network is its urban scope, which typically connects different areas and business centers within a city.

Advantages and Uses

The advantage of metropolitan fiber is that it provides highly reliable, high-speed connections for enterprises within cities. This is crucial for meeting the growing bandwidth demand, especially for industries that require fast data transfer and real-time communication, such as finance, health care, and media. The main uses include:

Financial trading networks: Financial institutions need low-latency, high-bandwidth connections to ensure fast execution of trades. Metropolitan fiber provides low-latency communication channels that help improve trading efficiency.

Data center links: High-bandwidth connections between data centers are essential for data backup, cloud computing and disaster recovery. Metropolitan fiber can support fast data transfer of large amounts of data.

Enterprise networks: Many enterprises need reliable, high-speed network connections to support their daily operations. Metropolitan fiber provides a solution that meets these needs.

Structure and Characteristics

Metropolitan fiber usually uses multimode fiber, which is a type of fiber that has a larger glass core, allowing multiple optical transmission modes. This structure allows for greater overall bandwidth potential, as more fibers can transmit more data. In addition, since metropolitan networks cover larger areas within cities, it allows for more unique and diverse route choices. This provides redundancy and fault tolerance, ensuring data can still be transmitted even if there is a failure in some part of the network.

Long-Haul Fiber

Location and Coverage

Long-haul fiber is a type of fiber optic network that covers long distances, typically spanning thousands of miles, connecting major markets and cities. A key feature of this fiber network is its long-distance connection, usually using routes that cross continents through points of presence (PoPs).

Advantages and Uses

The main advantage of long-haul fiber is its ability to connect distant geographic regions, providing high-bandwidth and reliable cross-market connections. This is essential for data transfers and global communications that span continents. The main uses include:

Global data transfer: Long-haul fiber connections that cross continents are key for global data transfer. They support the information exchange, cloud services and intercontinental communications of multinational enterprises.

Internet backbone: Long-haul fiber forms part of the internet backbone network, ensuring data transmission between different countries and intercontinental regions.

Multinational enterprises: Globalized enterprises need reliable cross-national connections to support their offices and facilities distributed in different geographic locations.

Structure and Characteristics

Long-haul fiber is mainly composed of single-mode fiber. These fibers have a smaller glass core, allowing only one mode of light transmission. This limits the amount of data that can be transmitted at once, but has no significant distance limitation.

The structure of long-haul fiber is more focused on long-distance transmission, rather than diverse route choices. This makes them very suitable for connecting distant geographic regions, without requiring complex routing.

Combining Metro and Long-Haul Fiber

For most enterprises, the combination of metro and long-haul fiber is the ideal solution. This hybrid approach allows them to connect to markets and meet customer demands anytime and anywhere. Enterprises can leverage metro fiber to connect their offices and data centers, while using long-haul fiber to connect different cities and global markets. This combination also provides flexibility and redundancy, ensuring that there are alternative paths available even if one connection fails. This is crucial for maintaining business continuity and availability.

Moreover, the structural differences between metro and long-haul fiber also allow enterprises to optimize their choices according to their specific needs. For example, for data center connections that require high bandwidth, metro fiber might be a more suitable option, as they have greater bandwidth potential. For global data transfers that span continents, long-haul fiber might be more attractive, as they focus on long-distance transmission without the need for diverse routes.

The Unlimited Potential of Dark Fiber

Full Control Over IT Assets

One major advantage is that dark fiber enables enterprises to have full control over their IT assets. Compared to traditional internet service provider (ISP) connections, dark fiber offers a higher degree of control. Enterprises can manage, configure and maintain their network devices independently, without being constrained by third-party vendors. This means that enterprises can customize their settings according to their own needs and priorities, without being affected by external factors.

This control also extends to the monitoring and adjustment of network performance. Enterprises can monitor network traffic, latency and bandwidth usage in real time, and make adjustments when necessary. This ability is vital for meeting changing business demands, especially for enterprises that need to respond quickly to market changes.

Infinite Scalability

One of the unique features of dark fiber is that it is virtually limitless. A major benefit of dark fiber is that it allows businesses to expand their network capacity as needed, without requiring major infrastructure changes. This is because dark fiber is actually fiber optic cable that has been installed underground but not activated or utilized yet. Once installed, they can be activated on demand, without requiring additional fiber cabling work.

This scalability is crucial for meeting the growing bandwidth demands. As businesses expand and undergo digital transformation, the need for more bandwidth becomes increasingly urgent. Traditional ISP connections usually have fixed bandwidth limits, requiring complex negotiations and upgrades with the providers, while dark fiber can meet these demands more quickly.

The Potential of Dense Wavelength Division Multiplexing (DWDM)

Dark fiber also unlocks the potential of Dense Wavelength Division Multiplexing (DWDM). DWDM is an advanced fiber optic technology that effectively splits the fiber into individual wavelengths across the entire spectrum, achieving greater capacity. This is very beneficial for businesses with large data needs, such as media, manufacturing, banking, etc.

With DWDM technology, a single fiber can carry multiple independent data streams, each with a different wavelength. This means that businesses can significantly increase their bandwidth without increasing the number of fibers. This is very useful for handling large-scale data transfers, video streaming, cloud computing and other high-bandwidth applications.

Higher Level of Resilience and Security

Another benefit of dark fiber is that it provides a higher level of resilience and security. Compared to traditional ISP options that share connections, dark fiber offers businesses an independent, private network connection. This means that businesses do not share their bandwidth with anyone else, reducing the risk of congestion and performance degradation.

This is vital for businesses that handle sensitive information, such as financial services, retail or healthcare sectors. Moreover, some industries require real-time information transmission, such as financial services, which have very high demands on network performance and availability. The high level of control and independence that dark fiber offers makes it an ideal choice for meeting these demands.

Adapting to Cloud and VoIP Capabilities

For businesses that want to leverage cloud computing and VoIP (Voice over Internet Protocol) capabilities, having a reliable network is essential. Cloud computing and VoIP applications rely on high-bandwidth, low-latency network connections to enable real-time communication and data transfer.

Dark fiber provides near-infinite capacity, which means that businesses can easily adapt to future bandwidth needs. This ensures that there are no performance issues or interruptions when using cloud applications and VoIP capabilities, thereby improving productivity and business reliability.