Design of all-fiber thulium laser in CW and QCW mode of operation for medical use

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• 作者：Debasis Pal ; Ranjan Sen and Atasi Pal
• 刊名：physica status solidi (c)
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：14
• 期：1-2
• 全文大小：1171K
• ISSN：1610-1642a

文摘

Fiber laser below 2000 nm is required for effective urological applications because of strong water absorption. Design of all-fiber thulium laser at this wavelength under pumping at 793 nm, utilizing cross relaxation mechanism, demands rigorous optimization of parameters as highly concentrated thulium doped silica has maximum gain at around 2010 nm. Length of the active fiber and the reflectivity of the output coupler have been optimized for maximum slope efficiency and output power. Counter propagating pumping scheme has been considered for better thermal management and good lasing efficiency. Spectral property and time domain response of the laser have been studied at different levels of output power. Lasing characteristics at 1910 nm, 1950 nm, 2000 nm and 2100 nm have also been investigated. The continuous wave lasing at 1950 nm with output power of 16.1 W having slope efficiency of 65.6% has been demonstrated. In quasi-continuous wave mode of operation, pulse energy in the range of 400 µJ to 5 mJ has been measured for the peak power of 16 W. The designed laser has been used successfully in human kidney stone breaking.