A highly efficient 57 pm Tm-doped fiber laser with two multimode fiber Bragg gratings

Abstract

An LD-clad pumped Tm-doped fiber laser is built with two multimode double-clad fiber Bragg gratings (FBGs) to generate narrow linewidth output around 2 µm. The slope efficiency of this laser system is 43.1% with respect to the launched pump power, corresponding to a quantum efficiency of 109%, which means that at least 9% of the doped thulium ions take part in the two-for-one cross relaxation process. Exploiting two multimode FBGs and wrapping the fiber onto an aluminum spool, a single peak narrow linewidth spectrum is generated. A 3 dB linewidth of 57 pm centering at 1996.2 nm is obtained at an output of 3.6 W.

Highly stable, efficient Tm-doped fiber laser—a potential scalpel for low invasive surgery

“…It has also been reported that a coherent beam combined can lead to an emittance of tens of watts at ~2 µm [12,13]. It is also worth adding that the above-mentioned configurations can be realized utilizing bulk optics, mainly used for launching pump power into an active medium [14][15][16] or are developed as all-fiber systems [17,18]. Comparing the two approaches, the latter one provides better compactness and stability, which is crucial for many applications.…”