Single-mode optical fibers with low cutoff wavelength and low bend loss

An optical fiber comprising:

• a silica-based core region comprising an alpha value less than 20, an outer radius r1 from about 4.0 microns to about 4.6 microns, a maximum relative refractive index Δ1MAX from about 0.28% to about 0.40%, and a core volume from about 4.5% Δ-micron2 to about 5.5% Δ-micron2;
• a depressed-index cladding region surrounding said core region, the depressed-index cladding region comprising an inner radius r2 such that r1/r2 is greater than about 0.4 and less than about 0.6, an outer radius r3, a minimum relative refractive index Δ3MIN less than about −0.2%, and a trench volume between about −50% Δ-micron2s and about −20% Δ-micron2;
• and
• an outer cladding region surrounding the depressed index cladding region, the outer cladding region comprising an outer radius r4,
• wherein the optical fiber comprises:
• a mode field diameter at 1310 nm from about 8.8 microns to about 9.4 microns,
• a 2 m cable cutoff from about 1120 nm to about 1260 nm,
• a bending loss at 1310 nm, as determined by the mandrel wrap test using a mandrel comprising a diameter of 15 mm, of less than 1.0 dB/turn, and
• a zero dispersion wavelength between 1300 nm and 1324 nm.