Modeling the optical nonlinear effects on DFB-RF laser based on the transfer matrix method

In this paper, the operation of pi-phase shifted distributed feedback Raman fiber (DFB-RF) laser above threshold condition is analyzed theoretically. The nonlinear optical phenomena such as self phase modulation (SPM) and cross phase modulation (XPM) have significant effect on the performance of DFB-RF laser. The numerical results show that the nonlinear effects cause to the saturation of output power and the value of saturated power is dependent on the fiber length. It is found that, the operation wavelength of stokes modes of DFB-RF laser varies in above threshold condition as a result of nonlinear optical properties of the fiber. Simulation is performed by using transfer matrix method to solve three coupled nonlinear wave equations which describe the propagation of pump, forward and backward Stokes waves. The nonlinear SPM and XPM effects are considered in the presented theoretical model. (C) 2019 Elsevier Inc. All rights reserved.