All-fiber-integrated single frequency tapered fiber amplifier with near diffraction limited output

作者:Zhou, Zichao; Zhang, Hanwei; Wang, Xiaolin*; Pan, Zhiyong; Su, Rongtao; Yang, Baolai; Zhou, Pu; Xu, Xiaojun
来源:Journal of Optics, 2016, 18(6): 065504.
DOI:10.1088/2040-8978/18/6/065504

摘要

We present an all-fiber single frequency high-power amplifier using tapered ytterbium-doped fiber (T-YDF) based on a master oscillator power amplification (MOPA) scheme. Different from previous laser amplifiers, the monolithic system is all-fiber-integrated, employing a large mode area (LMA) T-YDF and co-pump scheme. The LMA T-YDF is 7 m long and its core/inner cladding diameters are 20.4/237.1 mu m and 46.9/579.9 mu m in the input port and output port, respectively. In experiment, the laser amplifier is shown to generate up to 53W of single frequency laser with slope efficiency of 57.7%, which indicates more than a two times increase of the stimulated Brillouin scattering (SBS) threshold than common LMA fibers with core/inner cladding diameters of 20/400 mu m. At the highest output power, the M-2 factor is measured to be 1.25 and 1.20 in the X and Y directions. Results show that this T-YDF can be scaled up to even higher power when other SBS suppression methods are employed simultaneously.