(1) Extremely wide band, large communication capacity. Optical fibers have a much larger transmission bandwidth than copper or cables, the modulation characteristics of the light source of the optical fiber communication system, the modulation scheme, and the dispersion characteristics of the optical fiber. For a single-wavelength optical fiber communication system, the advantages of large optical fiber bandwidth can not be realized due to the electronic bottleneck effect of the terminal equipment. In general, various complicated technologies are used to increase the transmission capacity. In particular, the dense wavelength division multiplexing technology nowadays greatly increases the transmission capacity of optical fibers. At present, the transmission rate of a single-wavelength optical fiber communication system is generally 2.5 Gbps to 10 Gbps.
(2) Low loss, long relay distance. At present, the loss of commercial quartz fiber can be less than 0 ~ 20dB / km, so the transmission loss is lower than that of any other transmission medium. If the non-quartz system ultra-low loss optical fiber is used in the future, the theoretical loss can be reduced lower. This means that greater fiber-less communication distances can be crossed; for a long haul transmission line, the cost and complexity of the system can be significantly reduced due to the reduced number of relay stations.
(3) Anti-electromagnetic interference ability. Fiber raw materials are made of quartz insulation material, not easy to corrosion, and good insulation. An important feature associated with this is the immunity of optical waveguides against electromagnetic interference, which is immune to the effects of lightning, ionospheric changes and sunspot activity in nature and electromagnetic interference that is liberated by man and with High-voltage transmission lines installed in parallel or with the power conductor composite composite cable. This is particularly advantageous for communication systems in the area of strong electrical power such as power transmission lines and electrified railways. The fiber optic transmission system is also particularly suitable for military applications due to its immunity to electromagnetic pulse effects.
(4) No crosstalk interference, good confidentiality. In the course of radio wave transmission, the leakage of electromagnetic wave can cause the crosstalk of each transmission channel, and is easily eavesdropped, thus the secrecy is poor. Light waves are transmitted in the optical fiber because the optical signal is perfectly confined in the optical waveguide structure and any leaked rays are absorbed by the opaque wrapping around the optical fiber and the light leakage is very weak even at the turn, The total number of crosstalk interference adjacent channels will not appear at the same time outside the fiber optic cable, can not eavesdrop on the fiber optic transmission of information.
In addition to the above features, there are fine fiber diameter, light weight, soft, easy to lay; fiber raw materials rich in resources, low cost; temperature stability, long life. Because of the unique advantages of optical fiber communication, it can not only be used in the trunk line of communication, but also used in power communication control system for industrial monitoring and control, and its use in the military field is also more and more widely.