OPTICAL FIBER FOR APPLICATIONS REQUIRING HIGH SYSTEM OPTICAL SIGNAL-TO-NOISE RATIO PERFORMANCE AND LOW DEGRADATION FROM NONLINEAR IMPAIRMENTS

A optical fiber having core and cladding regions, a primary coating, and a secondary coating may be defined in part by a curve relating the microbend sensitivity to a ratio of the elastic modulus of the secondary coating to the elastic modulus of the primary coating (as plotted on respective y and x axes). The curve has a substantially peaked shape defined by a positive-slope region and a negative-slope region. The ratio of the elastic modulus of the secondary coating to the elastic modulus of the primary coating is within the positive-slope region. The outside diameter of the primary coating is in particular between about 155 and 200 microns, and that of the secondary coating between about 190 and 260 microns. The effective area of the fiber is between about 110 and 170 square microns, and the ratio of the secondary coating elastic modulus to that of the primary coating is less than about 1000.