A long haul optical fiber transmission system comprising: a transmitter adapted to transmit a signal with a modulated bit rate of at least 40 Gb/s; a composite optical fiber span; and a receiver optically coupled to the transmitter via the composite optical fiber span, wherein the receiver comprises a Raman and/or an erbium doped fiber amplifier for reverse pumping the 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 between 30km and 90km; 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; a third optical fiber having an effective area Aeff 3 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L3 and a nonlinear refractive index less than or equal to 2.2x10 -20 m 2 /W, wherein the third optical fiber is optically coupled to the second optical fiber; and a fourth optical fiber having an effective area Aeff 4 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L 4, and a nonlinear refractive index n 2 4 of less than or equal to 2.2x10 -20 m 2 /W, wherein the fourth optical fiber is optically coupled to the third optical fiber and the effective area Aeff 4 of the fourth optical fiber is greater than the effective area Aeff 3 of the third optical fiber; wherein 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. a transmitter adapted to transmit a signal with a modulated bit rate of at least 40 Gb/s; a composite optical fiber span; and a receiver optically coupled to the transmitter via the composite optical fiber span, wherein the receiver comprises a Raman and/or an erbium doped fiber amplifier for reverse pumping the 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 between 30km and 90km; 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; a third optical fiber having an effective area Aeff 3 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L3 and a nonlinear refractive index less than or equal to 2.2x10 -20 m 2 /W, wherein the third optical fiber is optically coupled to the second optical fiber; and a fourth optical fiber having an effective area Aeff 4 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L 4, and a nonlinear refractive index n 2 4 of less than or equal to 2.2x10 -20 m 2 /W, wherein the fourth optical fiber is optically coupled to the third optical fiber and the effective area Aeff 4 of the fourth optical fiber is greater than the effective area Aeff 3 of the third optical fiber; wherein 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. 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 between 30km and 90km; 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; a third optical fiber having an effective area Aeff 3 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L3 and a nonlinear refractive index less than or equal to 2.2x10 -20 m 2 /W, wherein the third optical fiber is optically coupled to the second optical fiber; and a fourth optical fiber having an effective area Aeff 4 of less than 120 μm 2, an attenuation of less than 0.180 dB/km, a length L 4, and a nonlinear refractive index n 2 4 of less than or equal to 2.2x10 -20 m 2 /W, wherein the fourth optical fiber is optically coupled to the third optical fiber and the effective area Aeff 4 of the fourth optical fiber is greater than the effective area Aeff 3 of the third optical fiber; wherein 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.