Patent ID: 8385705

Claim:
A single-mode optical fiber, comprising: a single-mode glass fiber comprising (i) a central core surrounded by an outer optical cladding, the central core having a radius r 1 and a positive refractive index difference Δn 1 with the outer optical cladding; (ii) an intermediate cladding positioned between the central core and the outer optical cladding, the intermediate cladding having a radius r 2 and a refractive index difference Δn 2 with the outer optical cladding, wherein the refractive index difference Δn 2 is less than the refractive index difference Δn 1 ; and (iii) a depressed trench positioned between the intermediate cladding and the outer optical cladding, the depressed trench having a radius r 3 and a negative refractive index difference Δn 3 with the outer optical cladding; and a substantially cured primary coating surrounding the single-mode glass fiber, the substantially cured primary coating possessing (i) an in situ modulus of less than about 0.65 MPa and (ii) a glass transition temperature of less than about −50° C.; wherein, at a wavelength of 1310 nanometers, the optical fiber has a nominal mode field diameter (MFD) between 8.6 microns and 9.5 microns; wherein, at a wavelength of 1550 nanometers, the optical fiber has bending losses of 0.25×10 −3 dB/turn or less for a radius of curvature of 15 millimeters; and wherein, at a wavelength of 1260 nanometers, the LP11 mode of the optical fiber is attenuated to 19.3 dB at a length of less than 90 meters.