  A large mode area single-mode optical fibre based on leaky mode filtering was
prepared by MCVD. The cladding structure discriminates the fundamental mode
from the higher order ones. A preliminary version has 25-$\mu$m core diameter
and 0.11 numerical aperture. A Gaussian-like mode with 22-$\mu$m MFD is
observed after 3-m propagation, in agreement with modeling.
