What is Dark Fiber and How can it Be Used?

Dark FiberHave you heard of “dark fiber?” This term refers to unused network infrastructure– optical fiber that’s not in use, with no light going through it. Since data is transported over fiber networks using light passed through cables, if and when no data is being transported, the fiber goes dark.

Where is Dark Fiber?

Where might you find dark fiber? In many cases, when companies initially install fiber optics they tend to overestimate the amount of infrastructure and cabling needed for the present time. It’s kind of like when a municipality builds extra roads in a neighborhood, “just in case” they’re needed at some time. Basically, there are many fiber optic networks these days which have extra capacity that’s not being used– plenty of dark fiber exists all over the U.S.A.

Here’s where it gets interesting: dark fiber networks currently exist because the available dark fiber is being leased from network providers and operators. These dark fiber networks are separate from main networks. Clients get to control them instead of the network provider being in charge. If this were the music industry, dark fiber would be your indie rock bands operating out of the mainstream, while typical fiber optic networks would be the major label bands everyone hears on the radio.

Dark Fiber Networks

Fiber Optic Systems How are dark fiber networks set up? They can be done in rings, point-to-point, or point-to-multipoint configurations. Companies who utilize these networks can expect superfast speeds and high security.

Dark fiber is able to excel in today’s world thanks to dense wavelength division multiplexing (DWDM). Multiple data signals can be transmitted at the same time over the same optical fiber. Data signals are kept separate thanks to different wavelengths. Thanks to DWDM, bandwidth is increased and more data can be sent. In essence, DWDM turns a single optical fiber cable into multiple “virtual” fibers.

Dark fiber networks have high capacity and don’t use as much power as more mainstream ones because of DWDM technology. Furthermore, signal strength is excellent and quite immune to interference.

For some time, companies and organizations have been choosing Ethernet broadband services, but dark fiber is making inroads as a viable competitor. In the past, dark fiber was a choice for large multinational corporations, but now it’s available and affordable for smaller companies.

Think of fiber networks like telephone wires of old– they run along a road on the one side of the road, right? Some buildings, thus, have easy access to them. Others do not. Fiber connections can be made, depending on location, and, of course, there’s a cost involved when adding to the overall network. Now if a company isn’t on the “main path” of fiber optics, it might make more fiscal sense to buy or rent dark fiber in order to create their own network. While it may take months to install, for those who plan ahead it can be a smart business decision.

Other Dark Fiber Applications

Especially important to certain companies or organizations is the ability to receive fiber that’s “all to themselves” for security purposes. Dark fiber allows this to be true. It can be fortified with AES-strength encryption, too, such that data cannot be intercepted even with a break. Meanwhile, with dark fiber, wavelengths can be configured as per needs, and easily reconfigured as needs change. If a company or organization wants to use as many wavelengths as possible, they can– or they can choose to just “light up” a few– it’s their decision.

Besides business applications, dark fiber has been studied for scientific purposes. Recently, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory found that dark fiber can be used as sensors for detecting earthquakes, the presence of groundwater, changes in permafrost conditions, and other subsurface goings-on. For example, researchers used fiber optic cables with novel processing techniques in order to monitor and measure seismic waves. The new technology is called “distributed acoustic sensing,” and works, thanks, in part, to dark fiber.

A lot of dark fiber exists buried underground across the country thanks to a huge rush in the 1990s. At that time, telecom companies all wanted to install fiber optic cables. Over time, the technology for transmitting data improved, to the point where many of those fibers went dark– they just weren’t needed anymore. That said, why waste them, right?

Fascinating Dark Fiber Uses

Fiber Optics and EarthquakesDark fiber is being experimented with in California with regards to earthquake research/detection as well as Alaska with respect to monitoring the stability of Arctic permafrost. Keep in mind that fiber is under the ocean as well as under the land, so it’s ubiquitous. Therefore, it makes sense to utilize it to the best of our current and future knowledge.

Today, dark fiber can and will help people figure out when and where earthquakes will occur, hopefully warning people “ahead of time” so they can get as safe as possible. And, of course, dark fiber can be used for business purposes, too. With more and more research, new uses for dark fiber are being discovered, including nuclear explosion monitoring, microearthquake characterization, and offshore submarine volcano detection. Expect more developments in the years to come.

If you need fiber optic installation or repair services, the fiber optic experts at Connected Fiber can help.

Written by Connected Fiber

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