Dark fibre stretches many miles across the country to provide redundancy for companies and ISPs. Dark fibre are optical cables that have been buried and installed throughout the country, but are current not in use. At first you may think thousands of miles of unused cables are wasteful, but when given an explanation, it actually makes a lot of sense. So why are companies putting so much effort into burying cables to just leave them dormant?
When you lay cables, the labor for digging the trenches, getting permits, and permission to dig is nearly the entire cost of the process. The actual cable only costs around 10% of the overall total. For this reason, companies like dark fibre networks from AMCOM will lay extra cables because it’s economically feasible. If they’re already digging the trench for other reasons, they might as well through in some extra fibre while they’re down there. This allows companies to expand in the future for little to no costs. It also provides redundancy; in case a line goes down, there’s a backup waiting to be used.
Since there’s so much used fibre around the country, the owners lease it out for use. Leasing fibre allows you to grow your company, while not investing millions of dollars on infrastructure. It also benefits the company leasing it because they’re receiving money for the extra expenses incurred to bury it in the first place. They can profit on the lines until they need it to expand upon their own network, or they can choose to just outright sell it.
Major tech companies that have astronomical amounts of data being transmitted every day are common purchasers of dark fibre. Google for instance is one of the biggest buyers, and is thought to hold more than any other company in the world. Makes sense, Google is starting to offer 1 gigabit internet service in a select few states. As their dark fibre network increases, they will be able to spread their ISP service to many more states in the future.