Dwdm Technology In The Telecommunications Trunk Transmission Network Applications Research

In recent years, the demand for large-scale, high-performance network transmission increases greatly with the rapid development of the global telecommunication market, especially the emergence of a series of new services such as the Internet, high-quality videoconference system and multimedia.The traditional optical fiber transmission system adopts the"one fiber, one wavelength"mode. Due to the limitation of components themselves, it is unable to make full use of vast bandwidth resources of optical fibers. As the most effective and economical means for optical fiber capacity expansion, the DWDM technology fully satisfies the development requirements of network bandwidth services. Moreover, it lays a solid foundation for the future shift to an all-optical transmission network.DWDM is a kind of optical fiber communication technology which can transfer the information containing multiple digital signals over the same fiber. DWDM expands system capacity by increasing wavelengths in the optical fiber. At the transmit end, it combines (multiplexes) optical signals of different wavelengths before transmitting them; at the receive end, it separates (demultiplexes) the combined optical signals in the optical fiber and then sends them to different communication terminals. The simulation for system configuration, which is based on the particular case of its application in the project, involves integratingly computing the configurations of optical amplification and optical multiplexing sections such as attenuation, dispersion compensation(DCM), PMD and so on, and respectively computing every channel of each optical amplification section and BER value and Q value of each optical multiplexing section. Briefly speaking, the DWDM is used to provide multiple virtual optical channels over the same physical optical fiber so that it greatly saves optical fiber resources.In the building net plan of this thesis, through the research and analysis of network resources and work quality, the specific characters of network covering area, application of existing optic fiber, the construction of network topology and capacity of transmission net were confirmed; according to the businesses demands of nowadays and future, speed-rate classes of Arterial transmission net were confirmed; on a basis of DWDM system design principle , output power of Optical Multiplexer Unit, Optical Amplifier and OIA were confirmed, and the equipment of each pilot site was distribute reasonably.In the conclusion of the paper, the testing of DWDM system is summarized, with detailed discussion given to every functional testing of OTU and the bit error testing of system functional tests. The result of engineering test shows all the test indexes are up to the standards.The states of present network and operation indicated, DWDM system of Chinese version were reliably, economical and practical, and the arterial transmission rate reached to 80×10Gbits/s, it could meet the present and a certain period of future needs of communication businesses.