Dwdm System And Its Key Technologies Of Raman Amplifier

Dense Wavelength Division Multiplexing (DWDM) is a large capacity fiberoptic transmission technique, which was developed and commercialized rapidly in the middle and later 1990s and widely employed firstly in Europe and North America. Presently, 16 and 32 channels DWDM equipment has been adopted on several busy lines in the eastern-coast economic dynamic area of China. After going into a new century, the needs of communication are hugely increased in terms of capacity, types of business and quality. Along with the popularization of PC and Internet, and the fast development of data business and other new type telecom businesses, there is an urgent demand for the increase of transmission capacity of DWDM equipment. At the same time, the development of DWDM also can be a good foundation for the future pure fiber-optic communication network. As we know, the bandwidth of singlemode fiber is almost infinity. However, the traditional Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SDH) adopted single wavelength light as the signal carrier wave during transmission, this kind of single channel transmission model is far less using the enormous bandwidth of fiber sufficiently. On one hand, we are worrying about getting crowding of the network; on the other hand, large amount of bandwidth resource is leaving unused. In such a circumstance, DWDM emerged as the times required. However, along with the increasing of channels of Wavelength Division Multiplex (WDM) and the accelerating velocity of single channel, the Nonlinear Effects of fiber have become the main restriction for the performance of system; meanwhile, long distance transmission also needs to overcome the impact of dispersion and nonlinear effects. Currently, Raman amplification is the priority technique to deal with those phenomena.This dissertation focused on DWDM system and the key technique of Raman amplification. DWDM, using the low-waste characteristic of singlemode fiber, adopts several, tens and even more different wavelength light as signal carrier waves, and allows different wavelength light transmitted in a fiber at the same time, to implement multiple light signals complex transmission in a fiber. DWDM technique has following five characteristics: extra-large capacity, data transparent transmission, maximum...