Theoretical modeling of holmium-doped fiber lasers pumped by laser-diodes around 1.15 µm.

At theoretical model of three levels describing Holmium-doped fiber lasers (HDFL) pumped by Laser-diodes 1.15 µm is presented. Based on the model, each of the efficiency, output power depending on fiber core radius, fiber length, and ion concentration of active media were investigated, using the MATLAB program (R 2019 a). The results show that at a doped fiber core radius, 2, 5 & 10 µm pumped with a power range of 10 - 100 W got an output power ranging from 5 to 55 W, respectively, while slope efficiency (η) was 31.3%. Output power was 2.7 - 4 W, η = 50% at a fiber length of 0.01 m, and 81.7 - 83 W, η = 19.6% at a fiber length of 0.5 m. The output power ranged from 107.8 to 109 W & η = 4.7% for 3 m fiber length. The threshold power value of Pth = 0.05 W at fiber core radius 2 µm and Pth = 0.006 W at 3 µm was then gradually slightly increased from 4 to 10 µm. As a result, the output power and efficiency are no longer reliant on the diameter of the fiber core. [ABSTRACT FROM AUTHOR]