Abstract

In this paper we investigate the Raman efficiency of different fibers. Our results are important for the design and optimization of repeaterless systems using remotely pumped Er-doped fiber amplifiers.^1,2 In these systems the Er-doped fiber amplifier is placed at a certain distance from the output end of the system and is remotely pumped by a 1.48-μm diode laser located at the output end. As the high-power pump laser propagates through the transmission fiber, it will provide Raman gain to the counterpropagating signal and, at the same time, will add noise to it. Indeed, Raman gains of 5.5 dB were reported in previous experiments using remotely pumped fiber amplifiers.¹ The amount of gain that the signal will experience, as well as the amount of noise generated, will depend on the pump and signal wavelengths, the pump power, and the characteristics of the fiber used.

© 1994 Optical Society of America