Dark fiber methods would be the unlit or unused parts of optical cabling systems; it may also refer to the elements of this cabling system not employed by the owner of the machine, but what can be rented out or sold away rather.  

Originally it referred to the entire capacity of this machine.  A well-engineered and planned method supplying surplus cabling may be a significant cost saving factor in preparation for future expansion. You can even see implemented fiber optic design via https://izakscientific.com/fiber-optic-design/ to know more about fiber-optic networks.

A well-designed network may have a huge number of unused optical cabling.  The cause of this is that the primary cost factor in installing a cable backbone is that the ancillary costs like labor, allows, ductwork, and channeling in addition to obtaining the contracts to cross others possessions.   

This is a sensible business decision because it reduces potential costs and eliminates the requirement to include extra cable at a later date because the requirement arises.  

Rather the cable is currently inset and must just be attached and activated. This also provides the cable operator the advantage of backup or redundant systems in place if a present cable becomes inoperable.

The significant telecommunication firms became the pioneer of the optical cable economies.  Using their built-in programs, they could prevent a good deal of the startup costs by putting the cable in their present systems.   

This guide finally drove the cost to get down the lines.  The absence of foresight caused a number of suppliers to finally seek bankruptcy protection.