Single-mode operation of a Raman fiber laser based on a multimode fiber has been demonstrated for what is to our knowledge the first time. Single-mode operation was achieved through the beam cleanup effect of stimulated Raman scattering in multimode fibers. The Raman laser, consisting of a 50-μm -core multimode fiber and a multimode Nd:YAG laser pump, produced an output beam corresponding to the fundamental mode of the fiber. The measured beam quality factor M<sup>2</sup> of the Raman laser beam was 1.66.
© 2004 Optical Society of America
(140.3510) Lasers and laser optics : Lasers, fiber
(190.2640) Nonlinear optics : Stimulated scattering, modulation, etc.
(190.4370) Nonlinear optics : Nonlinear optics, fibers
(230.4320) Optical devices : Nonlinear optical devices
(290.5910) Scattering : Scattering, stimulated Raman
Sung H. Baek and Won B. Roh, "Single-mode Raman fiber laser based on a multimode fiber," Opt. Lett. 29, 153-155 (2004)