Efficient and robust shooting algorithm for numerical design of bidirectionally pumped Raman fiber amplifiers

摘要

An efficient and robust shooting algorithm for the design of bidirectionally pumped Raman fiber amplifiers is proposed. First, a parameter S, new to our knowledge, called scaling vector, is introduced. This parameter is used in combination with the physical picture of stimulated Raman scattering to generate accurate initial guesses for the powers of backward pumps in the bidirectionally pumped Raman fiber amplifiers. Second, a modified Newton- Raphson method is developed. With an appropriate restriction for the adjustment of increments of initial guess attached, the modified Newton-Raphson method is used to correct the initial guesses to approach the true solution of the problem. By combining the method of initial value determination and the correction mechanism, 14 types of bidirectionally pumped Raman fiber amplifiers are designed. The simulation results show that the proposed shooting algorithm is more efficient and stable than most of the existing ones. Comparison with three other relevant methods reported in the literature is made to reveal the advantages of the new method.