Theoretical Analysis And Algorithm Study On Fiber Raman Amplifier Simulation

With the advantage of continuous broadband amplification, low noiseand flexible gain profile, fiber Raman amplifier (FRA) becomes more andmore important for high-capacity and long-haul wavelength divisionmultiplexing (WDM) fiber-optic communication systems. Numericalsimulation is an effective and economical method for FRA design and theperformance analysis of Raman-amplified transmission systems. In this thesis,several important issues in the numerical analysis of FRA are investigatedfrom the viewpoint of system design. Relevant investigations include:For the first time, the stiffness character of Raman amplifier propagationequations is analyzed, and a novel method for propagation equations isproposed to enhance the stability of numerical simulation. This method makesup the convergence limitation of the current algorithms, and meets the demandfor high power pump and long span FRA design.The performance of a pure iteration method for the two point boundaryvalue problems (TPBVPs) in Raman amplifier propagation equations isanalyzed. And based on this analysis, a novel weighted average method ispresented, which can remarkably enhance the convergence property ofnumerical simulation for TPBVPs. Compared with the existent algorithms, theweighted average method is of better convergence property with a satisfyingaccuracy, which promises a robust simulation tool for high power pump andlong span counter-pumped FRAs.A novel simulated annealing/tempering (SAT) algorithm for FRA gainequalization is proposed from the perspective of the real-world applications. Thismethod can rapidly obtain the global or near-global optimum solution for signal gainprofile, and has a good expandability.A two-step model for the simulation of Raman amplified transmission system isproposed and realized. In the first part, the configuration of FRA is designed andoptimized by using the SAT algorithm. And in the second part, the transmissionperformance is analyzed by using the commercial software VPI. With thecombination of our research productions and VPI, a complete simulation platform forRaman amplified transmission systems is established, which has been used in thebasic research of WDM optical networks (grand project of the NSFC).