Coherent beam combining of two all‑PM thulium‑doped fiber chirped pulse amplifiers  

作　　者：Bo Ren Hongxiang Chang Can Li Tao Wang Kaikai Jin Jiayi Zhang Kun Guo Rongtao Su Jinyong Leng Pu Zhou 

机构地区：[1]College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China [2]Nanhu Laser Laboratory,National University of Defense Technology,Changsha 410073,China [3]Hunan Provincial Key Laboratory of High Energy Laser Technology,National University of Defense Technology,Changsha 410073,China

出　　处：《Frontiers of Optoelectronics》2024年第2期33-42,共10页光电子前沿（英文版）

基　　金：supported in part by the National Key Research and Development Program of China(No.2022YFB3606000);in part by State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02).

摘　　要：In this paper,we report a coherent beam combining(CBC)system that involves two thulium-doped all-polarization maintaining(PM)fiber chirped pulse amplifiers.Through phase-locking the two channels via a fiber stretcher by using the stochastic parallel gradient descent(SPGD)algorithm,a maximum average power of 265 W is obtained,with a CBC efficiency of 81%and a residual phase error of λ/17.After de-chirping by a pair of diffraction gratings,the duration of the combined laser pulse is compressed to 690 fs.Taking into account the compression efficiency of 90%and the main peak energy proportion of 91%,the corresponding peak power is calculated to be 4 MW.The laser noise characteristics before and after CBC are examined,and the results indicate that the CBC would degrade the low frequency relative intensity noise(RIN),of which the integration is 1.74%in[100 Hz,2 MHz]at the maximum combined output power.In addition,the effects of the nonlinear spectrum broadening during chirped pulse amplification on the CBC efficiency are also investigated,showing that a higher extent of pulse stretching is effective in alleviating the spectrum broadening and realizing a higher output power with decent combining efficiency.

关 键 词：Coherent beam combining Thulium-doped fiber laser High-average power Chirped pulse amplifier 

分 类 号：TN722[电子电信—电路与系统]