In fiber optic technology, single mode fiber (SM) or monomode fiber is an optical fiber designed to propagate a single rail or a light mode as a carrier. Generally, single mode cable has a narrow core diameter of 8 to 10 µm (micrometers) that can travel at wavelengths of 810 nm and 1550 nm. The small single-mode fiber core size and single-light repulsion virtually eliminates any distortion that may be caused by overlapping light pulses. Therefore, single mode fiber optic cable provides the least signal attenuation and the highest transmission speeds of any fiber cable type. For these reasons, single mode optical fiber is the best choice for long distance data transmission.
Multimode fiber optic cables have a core diameter of 50 or 62.5 µm. They don't have as high a bandwidth as single mode cables, but still have a fairly high bandwidth. It is not ideal for those who want to run fiber optic cables over long distances; however, it is perfect for data centers and other locations with shorter cable lines. Apart from data centers, multimode fiber optic cables are mostly used in LAN networks and medical applications. Both single-mode and multi-mode fibers can transmit 10G speed. The important thing here is the distance. Multimode fiber optic cables can only support 300 to 400 meters. Single mode fiber optic cables can support lengths of up to 120 km. As a result it can be said that; While multi-mode fibers are used in datacenter applications and for short distance data transfer; singlemode fibers are used for data transfer over long distances.
Fiber optic applications have huge gains over other types of cabling. It is used in many areas with its high and quality signal carrying and high speed information transfer. Fiber Optic Cables consist of 3 parts: Core: It is the central part of the cable. This is the area where the light moves. Shell: Provides protection and guarantee of the transmitted site from environmental effects. Coating: It is the outermost surface. While the shell part provides coating from external effects, the part provides protection from mechanical and chemical factors in the external environment. Usage areas of fiber optic applications include LAN - WAN internet applications, common antenna and telephone exchanges, television systems, video conference systems, multimedia services and CCTV (Closed Circuit TV systems).