Development of Access Network

The concept of "access network" was put forward only in recent years. After years of development of telecommunication network, tremendous changes have taken place in the technology used and services provided. The introduction of new technologies such as traditional subscriber loop and passive optical network not only increases the functions and capabilities of subscriber loop, but also makes it more complex. Therefore, the concept of "access network" came into being at the historic moment. Life.
At present, large urban commercial districts in developed countries are gradually realizing the laying of optical fibers to buildings, and as soon as possible to achieve optical fibers to offices, optical fibers to desktops. New lines in new development zones directly use optical fibers, and have achieved optical fibers to roadside. In urban residential areas and rural areas, copper wires and cables will continue to be used for a long time, but "fiber to home" is the ultimate goal of access network development. Generally speaking, the cost of realizing "fiber-to-home" is very high. Generally, countries first develop fiber-to-roadside (FTTC) and fiber-to-building (FTTB) near users, and then transition to fiber-to-home (FTTH). At present, only Japan in developed countries, according to its own conditions, first proposed to achieve the goal of optical fiber to family in 2015.
Nowadays, the main reason that affects the development of optical access network is not technology, but cost. Until now, the cost of optical access network is still too high. For commercial users, the cost of using optical fiber and copper access network is very close. Therefore, the new commercial buildings are all directly using optical fiber to the building, and for important departments, optical fiber to the floor or optical fiber to the office. For the general residential users, the cost of using optical fiber is higher than that of copper wire. Therefore, optical fiber home is still in the experimental stage.
Whether it is for the construction of national information infrastructure or for the realization of Broadband Integrated Services Digital network, broadband access network technology, which integrates all kinds of networks such as telecommunication network, computer network, cable television network and various kinds of information such as language, digital, pictures, videos and so on, has become the key to the development of future communication network, and will be the research of international communication technology in the coming period. The hotspot of development and construction. In a sense, the technology development level of access network represents the modernization level of national communication technology.
Optical fiber access network is the inevitable trend of the development of optical fiber communication. Although the steps of developing optical fiber access network vary from country to country at present, the development goal of optical fiber to home is recognized as the access network. During the Eighth Five-Year Plan period, China has initially built an optical fiber trunk network. During the Ninth Five-Year Plan period, while further improving the optical fiber trunk transmission network, China has also stepped up the transformation and construction of access network. At present, the total length of optical cable laid in China has exceeded 1 million kilometers.
At present, the DWDM systems built in our country are basically point-to-point systems. Optical fiber access has been widely used in China's current access networks, including active optical access DLC (such as PDH or SDH as the transmission platform) and passive optical network (PON) optical access mode, to achieve FTTC, FTTB, lay the foundation for the ultimate realization of FTTH, and HFC technology is also used in broadcasting and television systems. Nowadays, optical fiber subscriber loop equipment has been widely used all over the country to replace the feeder in access network, and optical fiber gradually extends to users. In some areas, optical fiber to roadside (FTTC) access networks have been successfully constructed, and broadband access networks have also been successfully tested. At present, Guangzhou, Shanghai, Shenzhen, Beijing and other places have built broadband access networks. In addition to providing telephone and data services, broadband access networks can also transmit television, provide interactive video services such as TV on demand, home shopping, etc. A hybrid optical fiber coaxial network has been established to provide telephone and cable TV services to users by means of common cable splitting. It is expected that by 2004, China will carry out a major regulation. Construction of optical fiber access network for module.