What is the difference between fiber optic communications and optical communications? Please, everyone, thank you.

Fiber optic communication differs from wired electrical communication, which uses metallic media to transmit signals, and fiber optic communication, which uses transparent optical fibers to transmit light waves. Although light and electricity are both electromagnetic waves, the frequency range is very different. General communications cable maximum frequency of about 9-24 MHz (10 (6) Hz), fiber optic operating frequency of 10 (14) -10 (15)) Hz between. The most important advantages of fiber optic communications are: (1) large capacity. The fiber optic operating frequency is 8-9 orders of magnitude higher than the operating frequency currently used in cables, so the capacity developed is large. (2) Low attenuation. The attenuation per kilometer of optical fiber is more than one order of magnitude lower than the attenuation per kilometer of coaxial cable, which has the largest capacity. (3) Small size and light weight. It also facilitates construction and transportation. (4) Good anti-interference performance. Optical fiber is not subject to strong electrical interference, electrified railway interference and lightning interference, anti-electromagnetic pulse ability is also very strong, good confidentiality. (5) Save non-ferrous metals. General communication cables consume a lot of non-ferrous metals such as copper, aluminum or lead. Optical fiber itself is non-metallic, the development of optical fiber communication will save a lot of non-ferrous metals for the country. (6) Low cost. At present, the price of various cable metal materials on the market continues to rise, while the price of optical fiber has declined. This creates important preconditions for the rapid development of optical fiber communication. Fiber-optic communication is firstly used in the fiber-optic relay line between the telephone offices in the city, and then widely used in the long-distance trunk line network, which becomes the basis of broadband communication. Fiber-optic communication is particularly suitable for large-capacity, long-distance communication between countries, including domestic coastal communication and international long-distance submarine fiber-optic communication systems. At present, countries are further researching and developing fiber-optic communication systems for use in broad user access networks. With the continuous progress of many new technologies such as fiber optic amplifiers, optical wavelength division multiplexing technology, optical arc sub-communication technology, photoelectric integration and optical integration, fiber optic communication will be developed faster. Broadband, as the name implies, means a wide transmission bandwidth. Usually relative to the traditional narrow-band telecommunication network, in fact, there is no very strict definition, mainly refers to the same transmission medium, the use of special technology or equipment, the use of different channels for multiple (parallel) transmission, and the rate of 256Kbps or more. As for how much rate above is considered broadband, there is no international standard, some people say that more than 56K is broadband, some people say that more than 1Mbps can be considered broadband, and there is no final conclusion. ITU held a meeting on broadband communication earlier, the United States proposed to define the transmission bandwidth of more than 200Kbps as broadband, that is, the transmission of 200,000 "bits" per second, equivalent to 25,000 English characters or 12,500 Chinese characters. 200Kbps bandwidth so that the computer can be relatively clear images of a small window, if used to transmit the sound, the quality of the very high. Currently we use the telephone, although its transmission bandwidth in the 64K below, but already can distinguish familiar people through the sound quality, and with the development of digital compression technology, 8Kbps bandwidth is fully capable of transmitting coherent sound. The communication quality and capability of broadband are far beyond the narrowband communication system we commonly use at present, mainly in the aspect of data communication capability and image communication capability. We can imagine seeing the big screens of New York and Tokyo stock exchanges in the blink of an eye, with every tiny jitter clearly visible; we can also imagine playing a certain MTV song or a Hollywood blockbuster on demand at home at any time; broadband networks can even hold videoconferences for people distributed all over the world, and see each other's movements, facial expressions, and tones of voice as if they were only 1 meter apart. In other words, as long as the bandwidth is wide enough, any information can be transmitted most quickly and accurately. Broadband communications have developed very rapidly in the world in recent years. At present, the construction and use of broadband network penetration rate in the world's first is South Korea, its broadband network penetration rate of 57.3%; the United States of America's broadband network penetration rate of 11.l%; the European Union countries are also developing their own broadband network. China, on the other hand, is just starting out, but is developing rapidly. Broadband is mainly characterized by the following: High transmission rate (providing high-speed access of 100 megabytes to the building and 10 megabytes to the desktop). The maximum rate of each user is much greater than 56K and ISDN. this effectively ensures the clarity and consistency of the image, sound, data transmission, whether it is sending and receiving large files through e-mail or download images or software can be completed in an instant. Provide a variety of multimedia services (video-on-demand, tele-education, telemedicine, e-commerce, videoconferencing, making video calls, etc.). Relatively low cost. On the one hand, high-speed connections save a lot of online waiting time, making Internet access much less expensive. On the other hand, broadband access technology are not through the traditional telephone network switch, there is no problem of occupying the telephone line, no need to pay the telephone bill, further reducing the user's Internet costs. 24-hour casual access to the Internet, regardless of time constraints. Simple structure, easy to maintain (only need to add an additional device can be) Reliability and security, high scalability.