14.7mJ total output from a gani-switched Tm³⁺-doped double-clad silica fiber laser

A gain-switched Tm-doped double-clad silica fiber laser operating at a wavelength of approximately 2μm with moderate output energy is realized. A gain-switched Nd:YAG laser is used to pump the ³H₅ energy level of the doped Tm³⁺ ions at 1.064μm, and a maximum total output energy of 14.7mJ per pulse is produced at a slope efficiency of 39.5% (with respect to launched pump energy). As we know, this is the first time to realize the gain-switched Tm³⁺-doped double-clad silica fiber laser pumped at 1.064μm, and both the single pulse energy and the slope efficiency exceed the reported results that produced from single-clad Tm ³⁺-doped silica fiber laser in the past. The results of three different length fibers in experiments are present and contrasted. Because the absorption section at 1.064μm is only 2.5% at 0.79 μm in Tm ³⁺-doped silica fiber, we use three relative long fibers (the fiber. 1 length 35 m, fiber.2 length 8m, the fiber.3 length 1m.) to increase the absorption ratios. The laser threshold in fiber. 1, fiber.2 and fiber.3 is 37.5mJ, 39.4mJ and 48 mJ, and the slope efficiency is 39.5%, 11.6% and 1% respectively. The output peak wavelength from fiber. 1 fiber.2 and fiber.3 is 2.04μm, 2.01μm and 1.92μm measured by a monochromator respectively.