Design of a Continuous-Wave Ytterbium-Doped Tunable Fiber Laser Pump for Thulium-Doped Fiber Amplifiers

Fiber lasers are considered to be easily tunable, versatile, compact, maintenance-free, low-carbon footprint, and cost- efficient solutions in variety of applications as compared to conventional semiconductor lasers. These devices can be easily converted into pump sources to realize the Praseodymium-, Thulium-, and Holmium-doped fiber amplifiers. In this paper, we propose and demonstrate through numerical simulations, a 90-nm (1010–1100 nm)-wide tunable continuous-wave Ytterbium-doped fiber laser (YDFL) based high-power pump source for Thulium-doped fiber amplifiers (TDFAs). The YDFL-based pump source is realized by employing a single-ring cavity with forward pump source. The performance of the proposed YDFL is evaluated by considering an optimized pumping scheme, length of Ytterbium-doped fiber (YDF), and concentration of Yb^{3 +} ions. Output lasing powers of 36.5 dBm, 37.9 dBm, and 39.2 dBm are obtained at coupling ratios of 10%, 15%, and 20%, respectively, for lasing wavelength of 1043.157 nm. Average lasing powers of 35 dBm, 36.5 dBm, and 38 dBm are obtained for the entire spectral range at coupling ratios of 10%, 15%, and 20%, respectively. Furthermore, optical signal to noise ratio (OSNR) and linewidth of around 97.8 dB and 0.01 nm, respectively, are observed for lasing wavelength of 1043.157 nm. Finally, the affect of coupling ratio on output lasing power of the YDFL is also investigated. The proposed YDFL-based pump source is of low cost, simple, efficient, and highly stable.