514 W monolithic fiber laser with a femtosecond inscribed fiber bragg grating

Fiber lasers feature excellent characteristics for the development of high power laser systems. Additionally, the evolution of femtosecond inscription of fiber Bragg gratings (FBG) as narrowband reflective mirrors paved the way for the design of highly robust and compact monolithic systems [1, 2]. However, the tight power confinement of the light to the small fiber core gives rise to nonlinear effects hindering power scaling. This can be overcome by large mode area (LMA) fibers [3,4]. Here, we report on a monolithic continuous wave fiber laser at 1080.5 nm in an Yb-doped LMA fiber realized via a femtosecond inscribed FBG with an output power of 514 W, only limited by the pump power.