Experimental observation of multi-scale spatio-temporal structures with dark solitons embedded in a dissipative soliton

Abstract

The pulse embedded with dark solitons is theoretically predicted to be a transient state in the build-up dynamics or in the exploding pulsation of the bright dissipative soliton. Here, we observe experimentally a multi-scale spatio-temporal structure of the bright pulse ingrained with dark solitons with variable group velocities. The bright pulse with duration in the nanosecond range can coexist with dark solitons with durations in the picosecond range or longer. This allows for direct observation of the evolution of dark solitons in the time domain using a high-speed real-time oscilloscope. The lifetime and number of emerging dark solitons is demonstrated to be related to the pumping power and cavity net dispersion. Our study reveals that the amplifier noise and nonlinearity are the sources of dark solitons embedded in the bright dissipative soliton.