Franczyk M., Pysz D., Pucko P., Michalik D., Biduś M., Dłubek M., and Buczyński R.
We report development of ytterbium doped silica fiber with nanostructured core for laser applications. We study influence of non-continuous distributed Yb dopants on gain, beam quality, and fiber laser performance. The fiber core is composed of over 43 thousand nanorods with a central part doped with Yb. The diameter of each nanorod is 72 nm. With this method we obtained a flat refractive index profile with uniformity of 1.3 × 10−4 refractive index unit (RIU) despite the non-uniformity of 1.2 × 10−3 RIU in Yb doped preform rods used for the fiber development. We demonstrate a nanostructured core single-mode fiber laser with 61.8% of slope efficiency, and extremely low numerical aperture 0.027 of generated mode.
OPTICS EXPRESS, 2019, vol. 27(24), pp. 35108-35119, doi: 10.1364/OE.27.035108