Abstract

Since stimulated Raman scattering can convert energy from the higher frequency waves to the lower frequency waves, it has been used to amplify the decaying signal transmitted along the optical fiber. In a soliton-based fiber communication system, it has been verified theoretically and experimentally that the Raman scattering can provide a means for maintaining solitons over several thousand kilometers of fiber. In such a Raman compensation technique, quasi-cw pump waves are injected periodically into the fiber so that the decaying signal pulses are amplified during propagation. However, the research in the past is mainly focused on single-channel systems. In this study, we present a Raman compensation technique for wavelength-division-multiplexed systems. When multiple channels exist in a fiber, the energy conversion due to Raman scattering from the higher frequency channels into the lower frequency channels must be considered. In this presentation, we first point out the disadvantages of using one pump frequency for the entire multiple channels. Then we describe the technique of using multiple pump waves with different frequencies. In the pump scheme, each channel signal is amplified by the composite gain provided by all pump waves. It is shown that the proposed amplification scheme is quite general. The simulation results are also presented.

© 1989 Optical Society of America