Theoretical studies on gain characteristics of fluoride based hetero amplifier is thoroughly exhibited in the current research, which can be effectively used for S-band amplification in dynamic WDM optical network system, where the proposed hetero amplifier deals with both Raman amplifier and thulium doped fiber amplifier (TDFA) to achieve different characteristics such as flatten gain and low noise figure with respect to wavelength 1455 nm–1480 nm (S- band) for different channel spacing. Aside this, numerous parameters of hetero amplifier such as pump power, pump frequency, length of the fiber, doping concentration etc. are suitably manipulated to realize maximum gain, minimum gain variation ratio (GVR)and lower noise figure for aforementioned wavelength band. Further, simulation outcomes explored that a very low gain variation ratio of 0.14 dB, 0.4 dB, and 0.73 dB is obtained for channel spacing of 0.4 nm, 0.8 nm and 1 nm respectively. Moreover it has been revealed that the proposed hetero amplifier bestows a maximum gain of 23.44 dB at wavelength 1470.4 nm for 25 nm band (1455 nm–1480 nm) and lowest noise figure of -9.3 dB at wavelength 1470 nm for 1 nm channel spacing. Owing to the aforesaid remarkable upshots, the proposed hetero amplifier can be more conducive candidate for amplification in DWDM optical network systems.