Patent ID: 7164833

Claim:
An optical WDM transmission system using Raman amplification, said system comprising: a length of optical fiber including a core region; an optical transmitter for introducing a lightwave information signal into the optical fiber, the lightwave information signal including separate signal channels operating at at least three separate wavelengths, wavelength division multiplexed (WMD) to form the lightwave information signal; an optical pump source for introducing optical energy into the core region of said optical fiber, whereby the optical pump energy interacts with the lightwave information signal to produce Raman amplification of said lightwave information signal, wherein the invention is characterized in that the optical fiber has the following properties: low water peak at 1385 nm less than 0.4 dB/km; zero dispersion wavelength (ZDW) less than or equal to 1355 nm, with only one ZDW across the entire transmission band from 1310 to 1625 nm; chromatic dispersion (D) greater than 1 ps/nm-km at 1375 nm and between about 7.5 and about 9.5 ps/nm-km 1550 nm; and an effective area in the range of 50 to 65 μm 2 at 1550 nm.