Patent ID: 8538218

Claim:
A long haul optical fiber transmission system comprising: a transmitter comprising a modulated bit rate of at least 40 Gb/s; a receiver optically coupled to the transmitter with a composite optical fiber span, the composite optical fiber span comprising: a first optical fiber optically coupled to the transmitter and comprising an effective area Aeff 1 of at least 120 μm 2 , an attenuation α 1 of less than 0.180 dB/km, a nonlinear refractive index n 2 1 , and a length L 1 from about 60 km to about 90 km; and a second optical fiber optically coupled to the first optical fiber and comprising an effective area Aeff 2 of less than 120 μm 2 , an attenuation α 2 of less than 0.180 dB/km, a nonlinear refractive index n 2 2 and a length L 2 , wherein a sum of the length L 1 and the length L 2 is at least 160 km, the composite optical fiber span does not comprise a repeater between the transmitter and the receiver, and the composite optical fiber span does not contain any rare earth dopants, , wherein a total length of the composite optical fiber span is 400 km or less.