Multi-pumped tellurite-based Raman fiber amplifier based on Gaussian fitting of gain spectrum

The theoretical model and amplification principle of Raman fiber amplifier (RFA) are introduced. The gain curve and gain coefficient function which can accurately reflect the information of Raman gain spectrum (RGS) are obtained by the eighth-order Gaussian fitting of RGS of tellurite-based fiber. Combined with the technique of multi-pump, Raman power coupled wave differential equation is numerically solved by the fourth-order Runge–Kutta method. And Raman gain of each signal wavelength is obtained. According to the requirements of Dense Wavelength Division Multiplexing optical fiber transmission system for RFA, the designed tellurite-based Raman fiber amplifier (T-RFA) has improved the gain and bandwidth, and the smaller gain flatness is guaranteed. Finally, the average gain of the designed T-RFA obtained by Matlab numerical simulation is 25.518 dB, the maximum gain is 26.20 dB, the gain bandwidth is 56 nm and the gain flatness is 1.34 dB.