We report over 2 W of single spatial-mode output power at 1.5 µm from an 8-cm-long, large-core phosphate fiber laser. The fiber has a numerical aperture of simeq 0.17 and a 25-µm-wide core, heavily doped with 1% Er+3 and 8% Yb+3. The laser utilizes a scalable evanescent-field-based pumping scheme and can be pumped by as many as eight individual multimode pigtailed diode laser sources at a wavelength of 975 nm. Nearly diffraction-limited laser output with a beam quality factor M^2 simeq 1.1 is achieved by use of a simple intracavity all-fiber spatial-mode filter. Both spectrally broadband and narrowband operation of the laser are demonstrated.
© 2005 Optical Society of America
Alexander Polynkin, Pavel Polynkin, Axel Schülzgen, Masud Mansuripur, and N. Peyghambarian, "Watts-level, short all-fiber laser at 1.5 µm with a large core and diffraction-limited output via intracavity spatial-mode filtering," Opt. Lett. 30, 403-405 (2005)