Abstract
Optical fibers with improved bending loss characteristics have been developed intensively. A hole assisted fiber (HAF) can realize a superior bending loss characteristics by simply introducing several air holes around the conventional doped core. In this paper, we experimentally investigate the bending loss and cutoff wavelength characteristics of HAF taking into account the filling fraction of air holes. We also propose a novel technique for evaluating the long term reliability under ultra small bending condition. The validity of the proposed technique is successfully clarified experimentally.
