Optical fiber having negative dispersion, negative dispersion slope and large effective area

An optical fiber, comprising:

• a doped core region having an index of refraction n1;
• a cladding region having an index of refraction n2;
• a trench region between the doped core region and the cladding region and adjacent the doped core region, the trench region having an index of refraction n3;
• a first barrier region between the doped core region and the cladding region and adjacent the trench region, the first barrier region having an index of refraction n4;
• and
• a second barrier region between the doped core region and the cladding region and adjacent the first barrier region, the second barrier region having an index of refraction n5,
• wherein the optical fiber has a chromatic dispersion of approximately −40 picosecond/(nanometer-kilometer) and an effective core area, Aeff, that is greater than 30.0 μm at a wavelength of 1550 nm.

A method for making an optical fiber, comprising the steps of:

• forming a doped core region having an index of refraction n1;
• forming a trench region around the doped core region, the trench region having an index of refraction n3;
• forming a first barrier region around the trench region, the first barrier having an index of refraction n4;
• forming a second barrier region around the first barrier region, the second barrier region having an index of refraction n5;
• and
• forming a cladding region around the second barrier region, the cladding region having an index of refraction n2,
• wherein the doped core region, the cladding region, the trench region, the first barrier region and the second barrier region are formed such that 0.745%<(n1−n2)/n2<0.759%, −0.403%<(n3−n2)/n2<−0.394%, 0.152%<(n4−n2)/n2<0.166%, and 0.083%<(n5−n2)/n2<−0.041%.

An optical fiber preform, comprising:

• a doped core region having an index of refraction n1;
• a cladding region having an index of refraction n2;
• a trench region between the doped core region and the cladding region and adjacent the doped core region, the trench region having an index of refraction n3;
• a first barrier region between the doped core region and the cladding region and adjacent the trench region, the first barrier region having an index of refraction n4;
• and
• a second barrier region between the doped core region and the cladding region and adjacent the first barrier region, the second barrier region having an index of refraction n5,
• wherein the doped core region, the cladding region, the trench region, the first barrier region and the second barrier region are formed such that 0.745%<(n1−n2)/n2<0.759%, −0.403%<(n3−n2)/n2<−0.394%, 0.152%<(n4−n2)/n2<0.166%, and 0.083%<(n5−n2)/n2<−0.041%.