Beam quality and photodarkening comparison of tandem-pumped and directly diode-pumped ytterbium-doped fiber amplifiers  

作　　者：于海龙 王小林 周朴 肖虎 陈金宝 

机构地区：[1]Institute of High Energy Laser, College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, China

出　　处：《Chinese Optics Letters》2014年第A02期26-29,共4页中国光学快报（英文版）

摘　　要：Compared with the conventional diode-pumped ytterbium-doped fiber amplifiers （YDFAs）, tandem-pumped YDFAs are regarded as a better solution for high power scaling. In this letter, we compare and analyze the two types of pumping scheme with respect to beam quality （BQ）. The numerical model adopted by us is based on steady-state rate equations with consideration of transverse mode competition. The results show that tandem pumping is not only suitable for high power scaling but also has an advantage over direct diode pumping in BQ. For instance, the power fraction of fundamental mode in tandem pumping at 1030 nm is about 4~ higher than its corresponding value in direct diode pumping at 976 nm under the condition of counter-propagating pumping configuration with the same fiber parameters except cladding diameter. Mode selection by controlling dopant distributions and coiling the fibers is also simulated and discussed. Moreover, the simulation results show that the tandem-pumped YDFAs have lower photodarkening rate than the conventional YDFAs at part area of gain fiber, but there is no obvious difference between them from the mean DersDective of entire gain fiber.Compared with the conventional diode-pumped ytterbium-doped fiber amplifiers （YDFAs）, tandem-pumped YDFAs are regarded as a better solution for high power scaling. In this letter, we compare and analyze the two types of pumping scheme with respect to beam quality （BQ）. The numerical model adopted by us is based on steady-state rate equations with consideration of transverse mode competition. The results show that tandem pumping is not only suitable for high power scaling but also has an advantage over direct diode pumping in BQ. For instance, the power fraction of fundamental mode in tandem pumping at 1030 nm is about 4~ higher than its corresponding value in direct diode pumping at 976 nm under the condition of counter-propagating pumping configuration with the same fiber parameters except cladding diameter. Mode selection by controlling dopant distributions and coiling the fibers is also simulated and discussed. Moreover, the simulation results show that the tandem-pumped YDFAs have lower photodarkening rate than the conventional YDFAs at part area of gain fiber, but there is no obvious difference between them from the mean DersDective of entire gain fiber.

分 类 号：TN722[电子电信—电路与系统] TN248.1