Dissipative solitons in passively mode-locked fiber lasers

Abstract

Passively mode-locked fiber lasers due to their capability of generating ultrashort pulses, low cost and compact size have attracted considerable attentions. Conventionally, to generate ultrashort pulses the mode-locked fiber lasers were operated in the anomalous dispersion regime, where the natural balance between the fiber dispersion and optical Kerr effect shapes the mode-locked pulses into optical solitons. Recent studies have further shown that optical solitons could even be formed in the normal dispersion regime, where the soliton formation is a result of the mutual interaction among the cavity dispersion, fiber nonlinearity, laser gain saturation and gain bandwidth filtering. The solitons formed in the mode-locked fiber lasers are a type of dissipative solitons. The dynamics of dissipative solitons formed in a fiber laser is governed by the Ginzburg-Landau equation. Different from the conventional nonlinear Schrodinger equation (NLSE) type of solitons, dissipative solitons possess a number of new properties, such as scalable pulse energy, strong frequency chirp. Although there have been considerable theoretical and numerical studies on the properties and features of the dissipative solitons, no systematic experimental studies on them have been made, since such dissipative solitons were only experimentally observed recently. The current PhD thesis presents results of extensive experimental investigations on the features and dynamics of the dissipative solitons formed in passively mode-locked fiber lasers.