10.6 kW high-brightness cascade-end-pumped monolithic fiber lasers directly pumped by laser diodes in step-index large mode area double cladding fiber

A high-brightness single-end pumping monolithic fiber laser with 10.6 kW output power has been demonstrated through laser diode pumping schemes in traditional step-index large mode area double cladding fiber for the first time, and the configuration of the fiber laser has been detailed reported. To obtain a high power output by means of single-end pumping, a cascade-end pump configuration has been proposed based on a 30/900 mu m double cladding fiber, in which the maximal pump power can be increased significantly, and the requirement of thermal management has been reduced. To enable cascade-end pump configuration, a signal/pump combiner has been developed, the signal port of which can pass signal and pump light simultaneously. In experiment, this monolithic fiber laser achieves 10.6 kW output power at a center wavelength of 1080 nm with an optic-to-optic efficiency of 82.6% and a ss(FL) beam quality of 1.95. This single-end pumped fiber laser manifests good thermal management ability, and is promising for higher power scaling.