Grzegorczyk, Adrian, and Marcin Mamajek. “A 70 W Thulium-Doped All-Fiber Laser Operating at 1940 Nm”. Photonics Letters of Poland 11, no. 3 (September 30, 2019): 81–83. Accessed March 28, 2024. https://www.photonics.pl/PLP/index.php/letters/article/view/11-26.