As you know, there are two basic types of fiber optic system: multimode fiber and single-mode fiber. Multimode fiber is best designed for short transmission distances, and is suited for use in LAN systems and video surveillance. Single-mode fiber is best designed for longer transmission distances, making it suitable for long-distance telephony and multichannel television broadcast systems. For better understanding single mode fiber, I will list related information below.
 
Single Mode Fiber: Single Mode fibers have a small glass core, typically around 9 , can only send a pattern of light. Therefore, the intermodal dispersion is small, suitable for long-distance communication, but there is still a material dispersion and waveguide dispersion, so that single-mode fiber has higher requirements in the light source spectral width and stability, refers narrower spectral width, better stability. Later it was found at 1.31 m wavelength, single-mode fiber material dispersion and waveguide dispersion one is positive, another is negative, the number are just the same. So, 1.31��m wavelength fiber optic communication has become a very ideal working window, is now the main working band in practical fiber optic communication systems. The main parameters of 1.31��m conventional single-mode fiber are determined by the International Telecommunication Union ITU-T in recommendation G652, so this fiber optic is also known as G652.
 
The description of "Single-mode fiber" in the academic literature: General v is less than 2.405, the fiber has only one peak through, so called single-mode fiber, its core is very small, about 3 -10 microns, modal dispersion is small. The main factors affecting the fiber optical transmission band width are various dispersions, but mode dispersion is the most important. Dispersion of single mode fiber is small, so it can make light with a wide band transmission over long distances.
 
Single-mode fiber has a core diameter of 10 micron, allows single beam transmission, can relief the limitation of bandwidth and Modal dispersion. Because the single-mode fiber core is too small in diameter, it is difficult to control the beam transmission, so it needs extremely expensive laser as fiber optic light source, and the main limitation of the single mode fiber optical cable is Material dispersion, single mode fiber optical cable mainly using laser to obtain high bandwidth, because LED will release a large number of light source with different bandwidth, so the material dispersion requirement is very important.
 
Compared with multimode fiber, single-mode fiber can support longer transmission distance, in the 100Mbps Ethernet and 1Gigabit network, single-mode fiber can even support more than 5000m transmission distance.
 
From a cost perspective, due to fiber optic transceiver is very expensive, so the cost of using single mode fiber is higher than that of multimode fiber optic cable.