The dark fiber is an idle optical fiber that is used in network and telecom communications. It is also known as unlit fiber or black fiber. It is called dark because no light pulsation is being transmitted through it. There are number of ways to assemble a dark fiber network. The point-to-point or point-to-multipoint configurations are the mainly general ways to set-up whereas dense wavelength division multiplexing (DWDM) is a significant factor in the development and improvement of dark fiber. The dark fiber network provides scalability, enhanced security, compact network latency, and consistency.

One of the big advantages of Dark Fibre is it enables businesses to gain control of their IT estate and importantly, allows them manage capacity and to scale as needed as a fibre is limitless. Dark Fibre also enables the potential for Dense Wavelength Division Multiplexing, or DWDM, which effectively splits the fibre in to individual wavelengths across the spectrum enabling greater capacity to be achieved, which can be good for businesses with large data requirements like media, manufacturing and banks.