We present first all-fiber unidirectional ring thulium-doped laser, based on isolator-free theta cavity configuration and fiber Bragg mirror as filtering element. Laser provides 1W output power with 30% slope efficiency, and linewidth of about 0.2nm.
Tobias Kippenberg, Rui Ning Wang, Nicolas Volet, Junqiu Liu, Erwan Guillaume Albert Lucas, Arslan Sajid Raja, Jijun He