The emergence of new technologies is driving the continuous improvement of fiber optic communication capacity, which poses new requirements for the working wavelength range of fiber amplifiers. Therefore, there is an urgent need for fiber amplifiers that can achieve ultra wideband amplification.

In order to achieve ultra wideband Raman Fiber Amplifier (RFA) with gain ranges covering Super-C and Super-L bands, a transmission model of RFA was theoretically established, and numerical solutions for the transmission model of backward RFA were introduced. The pump power and wavelength range were selected considering the actual situation. Six pump wavelengths and seven pump lasers were used to simulate an optimized set of pump wavelength configurations in G.652 fiber. Based on the configuration of these pump wavelengths, experimental tests were conducted on three types of fibers: G.652, G.654, and Large Effective Area Fiber (LEAF). The simulation and experimental results were compared and analyzed.

The results show that a net gain of 18.07 dB and a gain flatness of 1.54 dB were obtained through testing in G.652 fiber. A net gain of 13.9 dB and a gain flatness of 1.21 dB were obtained through testing in G.654 fiber. A net gain of 21.99 dB and a gain flatness of 1.80 dB were tested in LEAF. The difference between the simulation results and the test results is less than 0.2 dB, and the difference in gain flatness is less than 0.4 dB.

The comparison between simulation results and test results indicates that the numerical solution method used in this paper can accurately predict the gain spectrum of RFA. The pump wavelength configuration used in this article has been experimentally verified to have significant gain and good gain flatness among the three types of fibers, which has reference value for wavelength selection in commercial ultra wideband RFA.