Coherent amplification of dual-frequency optical solitons in a doped fiber

It is found that the temporal behavior of sub-picosecond optical soliton-like pulses propagating through a fiber amplifier exhibits large deviations from the predictions based on standard soliton interaction theories. Both cases of adiabatic and pure coherent amplification of these dual-frequency solitons are studied. We show that it is possible to generate either a dual-frequency bound soliton state or a soliton train, The structure of the emerging optical state depends on the balance between the retarded coherent response introduced by an inverted two-level medium, nonresonant cubic nonlinearity, group-velocity dispersion, and Raman self-scattering. (C) 2001 Elsevier Science B.V. All rights reserved.