Rare Earth Doped Optical Fibers with Multi-section Core

iScience. 2019 Dec 20;22:423-429. doi: 10.1016/j.isci.2019.11.017. Epub 2019 Nov 15.


The gain bandwidth of a single-mode fiber is limited by the atomic transitions of one rare earth gain element. Here we overcome this long-standing challenge by designing a new single-mode fiber with multi-section core, where each section is doped with different gain element. We theoretically propose and experimentally demonstrate that this configuration provides a gain bandwidth well beyond the capability of conventional design, whereas the inclusion of multiple sections does not compromise single-mode operation or the quality of the transverse modal profile. This new fiber will be beneficial in realizing all fiber laser systems with few-cycle pulse duration or octave tunability.

Keywords: Fiber Optics; Optical Materials; Optics.