Optical fiber is short for optical fiber. It is a kind of fiber made of glass or plastic. It can be used as a light transmission tool, and the fiber part is made of plastic fiber. It is an integral part of the optical fiber. In the long river of the Internet, the optical fiber Parts have always been regarded as a dispensable role, but in fact the role of fiber parts is more useful than it looks.
Optical fiber parts account for a great deal of assistance in the network, and the advantages of fiber parts are numerous.
1, channel width
The width of the frequency band represents the size of the transmission capacity. The higher the carrier frequency, the greater the bandwidth of the signal that can be transmitted. In the VHF band, the carrier frequency is 48.5 MHz to 300 MHz. With a bandwidth of about 250MHz, it can only transmit 27 sets of TVs and dozens of sets of FM broadcasts. Visible light has a frequency of up to 100000 GHz, more than a million times higher than the VHF band. Although the bandwidth of the fiber is affected due to the different loss of the fiber to different frequencies, the bandwidth in the lowest loss region can reach 30000 GHz. At present, the bandwidth of a single light source only accounts for a small part of it (multi-mode fiber has a bandwidth of about several hundred megahertz, and good single-mode fiber can reach 10 GHz or more), and advanced coherent optical communication can arrange 2,000 lights in the 30000 GHz range. Carriers, wavelength division multiplexed, can accommodate millions of channels.
2, low loss
In a coaxial cable system, the best cable has a loss of more than 40 dB per kilometer when transmitting 800 MHz signals. In contrast, the loss of the optical fiber is much smaller, and the transmission of light of 1.31 um is less than 0.35 dB per kilometer. If 1.55 um of light is transmitted, the loss per kilometer is even smaller, which is less than 0.2 dB. This is 100 million times smaller than the coaxial cable's power loss, allowing it to travel farther. In addition, there are two characteristics of optical fiber transmission loss, the first is that all cable television channels have the same loss, do not need to be equal to the cable trunk must be introduced to equalize the equalizer; second, the loss of almost no change with temperature, do not worry Changes in the ambient temperature cause fluctuations in the level of the mains.
3, low weight
Because the fiber is very thin, single-mode fiber core diameter is generally 4um ~ 10um, the outer diameter is only 125um, plus waterproof layer, stiffeners, sheaths, etc., with 4 ~ 48 fiber optic cable diameter is less than 13mm, The diameter of the coaxial cable is much smaller than that of the standard coaxial cable, which is 47mm. With the glass fiber as the fiber, the specific gravity is small, so that it has the characteristics of small diameter and light weight, and the installation is very convenient.