Single made And Multi mode of Fiber Optic Cable

Single mode
In fiber-optic communication, a single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest. Single mode fibers are best at retaining the fidelity of each light pulse over longer distances and exhibit no dispersion caused by multiple spatial modes; thus more information can be transmitted per unit time giving single mode fibers a higher bandwidth in comparison with multi-mode fibers. A typical single mode optical fiber has a core radius of 5 to 10 µm and a cladding radius of 120 µm. Currently, data rates of up to 10 gigabits per second are possible at distances of over 60 km with commercially available transceivers.

Multi-mode optical fiber
(multimode fiber or MM fiber) is a type of optical fiber mostly used for communication over shorter distances, e.g. within a building. It can carry 1 Gbit/s for typical building distances; the actual maximum data rate (given the right electronics) depends upon the distance. Multi-mode fiber has a higher light-gathering capacity than single-mode optical fiber, making splicing less difficult, but its limit on speed × distance is lower. Because multi-mode fiber has a larger numerical aperture than single-mode fiber, it supports more than one propagation mode, resulting in larger modal dispersion and consequently higher pulse spreading rates, limiting information transmission capacity. Multimode fibers are useful for carrying larger amounts of power than single mode fibers. In such fibers, mode-filling becomes important, and mode scrambling attempts to fill the fiber to capacity, achieving an equilibrium mode distribution that utilizes all available fiber modes and has a more uniform energy density. These fibers are used when an intense beam is needed, as in optical pumping, laser welding, cutting, and marking.