Core-diameter adjustment, in analogy to doping management, is proposed in this letter for balancing thermal load and nonlinear effects. In this scheme, the core-to-cladding ratio increases with increasing core diameter along the direction of signal and pump propagation. An all-fiber-integrated Yb-doped master oscillator power amplification (MOPA) is successfully demonstrated. Two segments of fiber with different core diameters but same inner-cladding diameters and doping levels are spliced together and used as gain fibers in the last stage. A maximum average output power of 200 W at an overall slope efficiency of 71% is achieved from the MOPA with a pulse energy of 2 mJ and peak power as high as 80 kW.
© 2013 Chinese Optics Letters
Lasers and Laser Optics
Songtao , Ziwei Wang, Zhaokun Wang, Jing He, Jun Zhou, and Qihong Lou, "All-fiber, high-average-power nanosecond laser based on core-diameter adjustment," Chin. Opt. Lett. 11, 091402- (2013)