We consider large-mode area photonic crystal fibers for visible applications
where micro-deformation induced attenuation becomes a potential problem when
the effective area A_eff is sufficiently large compared to lambda^2. We argue
how a slight increase in fiber diameter D can be used in screening the
high-frequency components of the micro-deformation spectrum mechanically and we
confirm this experimentally for both 15 and 20 micron core fibers. For typical
bending-radii (R~16 cm) the operating band-width increases by ~3-400 nm to the
low-wavelength side.Comment: Accepted for Optics Letter