A. Brignon et al., Multimode to single-mode conversion of a Yb-doped fiber amplifier with a photorefractive Rh : BaTiO3 crystal, APP PHYS B, 72(6), 2001, pp. 789-791
We present a technique to convert a multimode-transverse beam obtained from
a multimode large core fiber amplifier into a single-mode beam by means of
two-wave mixing in an infrared-sensitive Rh:BaTiO3 crystal.