The Principle And Design Of Flat Gain Distributed Raman Fiber Amplifier

The optical fiber communication systems are developed into high-speed, wide-band and long-distance optical fiber communication systems with huge capacity. As the most widely used method in the backbone communication networks, dense wavelength division multiplexing technology has made remarkable progress. The enhancement of the transmission speed leads to the in crease of the input power, at the same time the transmission with huge capacity needs the further reduction of the channel separation in the existing communication windows. All of this makes nonlinear effects which has been ignored in the low-bit rate linear systems distinguished, which brings forward the new request of optical fiber amplifiers. The future amplifiers must be the distributing amplifiers, which have not only flat gain but also wide-band and the characteristic of the arbitrary band amplification. As far as it goes, fiber Raman amplifiers are the sole amplifier which can be competent. More and more people pay attention to fiber Raman amplifier and research on it. This paper gives theoretical analysis of fiber Raman amplifier. And with the method of numerical analysis, an arithmetic method which can run in computer is developed. Then software designed for Gain Flatness FRA simulation is simply introduced. Using the software to simulate the FRA. Several flat gain distributed Raman fiber amplifiers that meet the demand of business have been designed. The results shows that the software can well meet the demand of simulation of FRA.The main research contents and results are given as follows:(1) The characters of several kinds of optical amplifiers are compared. And the properties, applications and developments of fiber Raman amplifier are recounted, which highlights the meaning of new research.(2) The basic theory of Raman scattering and the characteristics of stimulated Raman scattering in fiber are detailed. The properties of fiber Raman amplifier, such as gain property, noise property as well as the structure of RFA model are discussed.(3) The mathematics'model of fiber Raman amplifier is given at first. Then based on the model, an arithmetic method to simulate gain process of FRA is produced.(4) The theoretical model is established which is used to simulate the detection of single wavelength signals and analyze the output characteristic. With the application of software engineering, the design of FRA simulation software is described. Using the software to simulate the FRA, several flat gain distributed Raman fiber amplifiers that meet the demand of business have been designed . The results of simulation indicate that the software can be applied to the simulation work in FRA design well.