Corning Incorporated
Low bend loss optical fiber with a chlorine doped core and offset trench

Abstract:

An optical fiber includes (i) a chlorine doped silica based core having a core alpha (Core.sub..alpha.).gtoreq.4, a radius r.sub.1, and a maximum refractive index delta .DELTA..sub.1max % and (ii) a cladding surrounding the core. The cladding surrounding the core includes a) a first inner cladding region adjacent to and in contact with the core and having a refractive index delta .DELTA..sub.2, a radius r.sub.2, and a minimum refractive index delta .DELTA..sub.2min such that .DELTA..sub.2min<.DELTA..sub.1max, b) a second inner cladding adjacent to and in contact with the first inner cladding having a refractive index .DELTA..sub.3, a radius r.sub.3, and a minimum refractive index delta .DELTA..sub.3min such that .DELTA..sub.3min<.DELTA..sub.2, and c) an outer cladding region surrounding the second inner cladding region and having a refractive index .DELTA..sub.5, a radius r.sub.max, and a minimum refractive index delta .DELTA..sub.3min such that .DELTA..sub.3min<.DELTA..sub.2. The optical fiber has a mode field diameter MFD at 1310 of .gtoreq.9 microns, a cable cutoff of .ltoreq.1260 nm, a zero dispersion wavelength of 1300 nm.ltoreq.zero dispersion wavelength.ltoreq.1324 nm, and a macrobending loss at 1550 nm for a 20 mm mandrel of less than 0.75 dB/turn.