OPTICAL TRANSMISSION SYSTEM EMPLOYING ERBIUM-DOPED OPTICAL AMPLIFIERS AND RAMAN AMPLIFIERS

摘要

In an optical communication system that includes a transmitting terminal, a receiving terminal, and an optical transmission path optically coupling the transmitting and receiving terminals and having at least one rare-earth dope d optical amplifier therein, a second optical amplifier is provided The second optical amplifier includes a first portion of the optical transmission path having a first end coupled to the transmitting terminal and a second end coupled to a first of the rare-earth doped optical amplifiers. In addition, the second optical amplifier includes a pump source providing pump energy to the first portion of the optical transmission path at one or more wavelength s that is less than a signal wavelength to provide Raman gain in the first portion at the signal wavelength.