Power stable robust femtosecond written fiber Bragg gratings for 2 µm polarized fiber lasers

We present power stable fiber Bragg gratings for linear fiber lasers in the 2 µm wavelength range. The FBG were inscribed through the coating material using infrared femtosecond laser pulses. By improved inscription parameters signal light scattering at the induced structure resulting in heating and shifting of the resonance laser was minimized. A stable linear polarized fiber laser at 2 µm with an output power of 50 W was implemented.