Three-level all-fiber laser at 915 nm based on polarization-maintaining Nd3+-doped silica fiber

作者：Wang, Yafei; Li, Xingyu; Wu, Jiamin; Peng, Xiulin; Cao, Jiangkun; Yang, Changsheng; Xu, Shanhui; Yang, Zhongmin; Peng, Mingying^*

来源：Chinese Optics Letters, 2020, 18(1): 011401.

DOI：10.3788/COL202018.011401

• fiber laser
• laser materials
• neodymium

Nd3+-doped fiber lasers at around 900 nm based on the F-4(3/2)-> I-4(9/2) transition have obtained much research attention since they can be used as the laser sources for generating pure blue fiber lasers through the frequency doubling. Here, an all-fiber laser at 915 nm was realized by polarization-maintaining Nd3+-doped silica fiber. A net gain per unit length of up to 1.0 dB/cm at 915 nm was obtained from a 4.5 cm fiber, which to our best knowledge is the highest gain coefficient reported in this kind of silica fiber. The optical-to-optical conversion efficiency varies with the active fiber length and the reflectivity of the output fiber Bragg grating (FBG), presenting an optimal value of 5.3% at 5.1 cm fiber length and 70% reflectivity of the low reflection FBG. Additionally, the linear distributed Bragg reflector short cavity was constructed to explore its potential in realizing single-frequency 915 nm fiber laser. The measurement result of longitudinal-mode properties shows it is still multi-longitudinal mode laser operation with 40 mm laser cavity. These results indicate that the Nd3+-doped silica fiber could be used to realize all-fiber laser at 915 nm, which presents potential to be the seed source of high-power fiber laser.