The gain and noise figure comparison of single‐pass, double‐pass, and dual‐stage triple‐pass thulium‐doped fiber amplifiers in S‐band with thulium‐doped fiber optimization

Abstract

AbstractThis study presents a comparison of three different S‐band thulium‐doped fiber amplifiers (TDFA) designs. The gain performances of the amplifiers are analyzed based on each scheme, separately. With −20 dBm input power, to provide ground‐state and excited‐state absorptions, the 1050 nm pump is used in all designs. The thulium‐doped fiber (TDF) lengths are optimized for maximum gain by using the single parameter single result optimization of Optisystem 18.0 software. A reflector is integrated into the double‐pass and dual‐stage triple‐pass TDFA to allow double propagation. Compared to double‐pass TDFA, in dual‐stage triple‐pass TDFA design, gain values increased without changing the stable bandwidth. 42.77 dB gain is demonstrated for two optimized TDF lengths; L1: 5 m and L2: 4.8 m, while noise figure values are higher than the other schemes. This comparison is important to show that the dual‐stage triple‐pass TDFA design could be suitable for obtaining higher gain in wider stable bandwidth in the fiber optic communication systems.