Partially coherent dissipative-soliton resonances in lasers

Dissipative-soliton resonance (DSR) is theoretically predicted to enable unlimited energy scaling while maintaining a constant power in dissipative systems. It has traditionally been regarded as a fully coherent structure. Here, through comprehensive simulations, we show that DSRs can exhibit partial coherence, characterized by stochastic temporal and spectral dynamics. Under appropriate saturation power of a nonmonotonic saturable absorber, the pulse develops a strong nonlinear chirp induced by self-phase modulation, which, in conjunction with normal dispersion, gives rise to wave-breaking-induced temporal fringes and the chaotic proliferation and decay of dark solitons. Concurrently, spatiotemporal intermittency emerges across the pulse plateau in the form of irregular patterns. These dynamics lead to stochastic temporal evolution and the degradation of spectral coherence, quantified by the decay of first-order spectral coherence between successive pulses. Nevertheless, the partially coherent DSR still exhibits characteristics similar to those of the coherent DSR, such as constant power and a pulse duration that increases with pump strength. Our results provide new physical insight into the coherence properties of DSRs and offer practical criteria for experimentally identifying the widely observed flat-top square pulses.