Matrix-Based Rate-Equation Modeling of Bismuth-Doped Fiber Amplifiers for Wideband Optical Communications

We present an improved matrix-based rate-equation model for simulating the behavior of Bismuth-doped fiber amplifiers (BDFAs) across ultra-wide wavelength ranges. The model accounts for multiple Bismuth active centers (BACs), treated as independent dopants with distinct spectroscopic properties, and incorporates an automatic optimization routine that iteratively refines uncertain input parameters by fitting simulations to experimental data. This approach allows accurate modeling of BAC dynamics while compensating for incomplete or uncertain input data on the characteristics of the different active centers. The model is validated through comparison with experimental results for BDFAs based on phosphosilicate and germanosilicate fibers operating in the O-, O+E-, and E-bands, showing excellent agreement for both gain and noise figure spectra under different pumping conditions. The proposed framework significantly improves the predictive accuracy of BDFA simulations and provides a practical tool for the design and optimization of next-generation wideband optical fiber amplifiers.