Many networks use single mode fiber for fast communication. It also gives strong connections across cities or countries. It lets only one light path go through. This. In fiber-optic communication, a single-mode optical fiber, also known as fundamental- or mono-mode, is an optical fiber designed to carry only a single mode of light - the transverse mode. Modes are the possible solutions of the Helmholtz equation for waves, which is obtained by combining. Single mode cable is commonly used in long-haul, high-speed communication systems, such as telephone and cable television networks, because it can transmit data over longer distances without the need for repeaters. Higher-order modes like LP 11, LP 20 etc.