Evaluating the effect of doping concentration and doping radius on the gain of silica based Thulium doped fiber amplifier

Thulium doped fiber amplifier is the most capable amplifier candidate for the Wavelength Division Multiplexing (WDM) systems working in S-band. Fluoride TDFA (Thulium doped fiber amplifier) provide better gain characteristics than the silica TDFA because of relatively low phonon energy of Thulium in fluoride host. On the other hand Silica TDFA has many advantages over Fluoride TDFA. In this paper gain evaluation of silica TDFA for doping concentration 20ppm and 80ppm for varied doping radius from 0.3μm-1.3μm has been done. The main objective of the paper is to find the TDFA parameters which yield better gain. It has been observed that with the triple pumping (1050nm+1400nm+800nm), the maximum gain of 29.63dB at 1470nm has been obtained for the 80ppm concentration with 0.7μm doping radius.