Abstract

Optical dark solitons are shown to undergo amplification and compression under the influence of a constant gain in the nonlinear Schrödinger equation. When the gain is small, the pulse follows a simple adiabatic, perturbative expression. For a fundamental dark soliton input, the pulse remains a single hyperbolic tangent shape and its duration decreases exponentially as a result of the gain. When the gain is large, secondary dark solitons¹ are generated and the pulse duration fails to follow the exponential rule during the initial stage of propagation. The duration does, however, decrease exponentially at sufficiently long traveling distances. This property of dark solitons can be utilized to amplify and to compress an initially broad dark pulse into a dark soliton of short duration. Stimulated Raman scattering can be used as a gain mechanism.² The optical power and time duration requirement in generating dark solitons can thus be relaxed as a consequence of this property.

© 1990 Optical Society of America