Small diameter low attenuation optical fiber

An optical fiber comprising:

• a core, said core having an outer radius r1, wherein r1 is 3.6 microns to 5.4 microns;
• a cladding surrounding said core, said cladding having an outer radius r4, wherein r4 is less than 45 microns;
• a primary coating surrounding said cladding, said primary coating having an outer radius r5 and a thickness tP>8 microns, an in situ modulus EP, wherein EP is 0.35 MPa or less, and a spring constant χP<1.6 MPa, where χP=2EP r4/tP;
• and
• a secondary coating surrounding said primary coating, said secondary coating having an outer radius r6 and a thickness tS=r6−r5, and an in situ modulus ES of 1200 MPa or greater,
• wherein tS is greater than 10 microns, said outer radius r6 is 85 microns or less, and said fiber has a mode field diameter MFD greater than 8.2 microns at 1310 nm, a fiber cutoff wavelength of less than 1310 nm, and
• said fiber exhibits a bend loss when wrapped around a mandrel having a diameter of 10 mm, of less than 1.0 dB/turn at a wavelength of 1550 nm, and
• said fiber exhibits a puncture resistance load greater than 30 grams and a wire mesh drum microbending attenuation of less than 0.5 dB/turn 0.5 dB/km at a wavelength of 1550 nm.