Coherent Beam Combining of Two Tm-doped Fiber MOPAs with Output Power of 50 W
Thulium-doped fiber lasers operating at~2 μm band have significant application prospects in fields such as eye-safe lidar,remote sensing,medical care and nonlinear frequency conversion.However,due to thermal damage,mode instability and nonlinear effects,the output power level of single Tm-doped fiber laser was limited,which confined the development of Tm-doped fiber laser.Coherent beam combining(CBC)is an effective method to improve power level of fiber lasers.In this paper,we demonstrated CBC of two Tm-doped fiber master oscillator power amplifiers(MOPAs)with total output power reaching 50 W.The output powers of the both MOPAs can reach~25 W when the pump power of each MOPA was~55 W.Single frequency dithering technique was used to implement active phase locking in feedback loop of the CBC system.When the feedback loop was implemented,phase noises below 700 Hz in the system were compensated effectively,and the far field intensity patterns were highly stable compared with the fluctuating patterns obtained when the feedback loop did not work.The fringe contrast was increased from~0.34 in open loop to~0.90 in closed-loop.These results indicate that the system we presented is a promising way to increase the output power of Tm-doped fiber lasers.Since the output power of the system is pump-limited,its reasonable to believe that higher output power at~2 μm could be obtained via CBC,if more channels are combined together and/or the power of each channel is further scaled up.
Xiaoxi Jin Xiong Wang Xiaolin Wang Yanxing Ma Pu Zhou
College of Optoelectronic Science and Engineering National University of Defense Technology,Changsha 410073,China
国际会议
Progress in Electromagnetics Research Symposium 2014(2014年电磁学研究新进展学术研讨会)
广州
英文
2483-2486
2014-08-01（万方平台首次上网日期，不代表论文的发表时间）