Dependence of peak gain on pump wavelength, pump power, numerical aperture and doping concentration of silica-based thulium doped fiber amplifier (TDFA) for 2 mu m region

In this paper dependence of peak gain of TDFA on the pump power is investigated. Here, four pumps of wavelength 1050 nm, 1560 nm, 1700 nm, 1740 nm have been used individually. The numerical aperture values of 0.3 and 0.4 for each pump wavelength have been considered. Also, ion densities of 15.6x10(24) m(-3), 20x10(24) m(-3), 30x10(24) m(-3), 40x10(24) m(-3) are set for each pump wavelength. A varied pump power from 20 mW to 300 mW has been used. In this way, eight simulation cases have been carried out for each pumping scheme and the gain curves are plotted to check the dependence of peak gain on pump power. It has been observed that the numerical aperture 0.4 gives better gain as compared to 0.3 in every pumping case. It is found that as the pump power increases, peak gain also increases. The peak gain is obtained at 1830 nm wavelength in each pumping case. For pump power 300 mW, the maximum peak gain of 19.4dB has been found for 1050 nm pump. The peak gain values found in the cases of the 1560 nm, 1700 nm and 1740 nm pumps are 33.39dB, 34.088dB, 34.34dB, respectively.