Large mode area leaky optical fiber fabricated by MCVD

A large mode area single-mode optical fiber based on leaky mode filtering has been prepared by modified chemical vapor deposition (MCVD) technique. The fiber has a leaky cladding, which discriminates the fundamental mode from the higher order ones. A preliminary version has 25-µm core diameter and 0.11 numerical aperture. A Gaussian-like mode with 22-µm mode field diameter has been observed after 3-m propagation, in agreement with modeling.