In the system of optical fiber communication, optical frequency as the carrier frequency is much higher than, and as a medium and low loss optical fiber coaxial cable than a lot, so relative to the cable or microwave communication, optical fiber communication has six unique advantages.
Comparison of cable and optical fiber loss band machine table, the table can be seen only suitable for basic cable with low data rate of the local area network (LAN), high-speed local area network (>100Mbit/s) and metropolitan area network (MAN) must be used in optical fiber.
Two, the loss of small, long distance relay
The table shows that the transmission loss per kilometer cable usually to dozens of DB in several dB, and the loss is 3 at the wavelength of 1.55um optical fiber cable is usually only 0.2dB/km, the loss was significantly greater than the fiber, or even several orders of magnitude larger.
Three, light weight, small size
Due to the size and weight of the cable are relatively large, must be carefully handled grounding and shielding problems during installation, the cable is not suitable for small applications, such as ships and aircraft. However, light weight, small size, very suitable for such occasions.
Four, anti electromagnetic interference performance is good
The fiber is made of electrically insulating quartz material, optical fiber communication lines are not damaged all kinds of electromagnetic interference and lightning, so no metal reinforced cable is very suitable for high voltage power lines around the strong electromagnetic interference, and the use of oil, coal and chemical plants and other inflammable and explosive environment.
Five, the leakage of small, good confidentiality
In today's society, the country's political, military and economic intelligence needs to be kept secret, and the economic and technical information of the enterprise has become the target of competition. Therefore, the security performance of the communication system is often a problem that the user must consider. Now listen to have been able to do in the coaxial cable from a few thousand meters away from the transmission of the signal transmission cable, but the cable signal eavesdropping is difficult. The leakage of the transmission signal in the optical fiber is very weak, even in the curved section can not be tapped. Without special tools, optical fiber can not be connected, so it is very safe in the transmission, which has an important significance for the military, political and economic.
Six, saving metal materials, is conducive to the rational use of resources
The manufacture of coaxial cable and wave tube of metal material on the earth's reserves is limited, while the manufacture of optical fiber quartz in the earth's reserves is extremely rich.
In short, the optical fiber communication is made of quartz glass and plastic, is a good electrical insulator, excellent, and the optical signal in the optical fiber transmission is not easy to leak, so there is no danger, electromagnetic interference, grounding, shielding and have poor confidentiality, with advantages of good transmission the optical fiber, become by far the best information transmission quality, therefore no matter in or in the backbone network, access network, optical fiber communication has made rapid development.