Coherence memory and amnesia in a mode-locked Mamyshev oscillator

Self-organization of temporal modes in mode-locked lasers usually starts from quantum noise. In this process, incoherent spontaneous emission is steered into coherent ultrashort pulses by dissipation and nonlinearity. In this work, we investigated self-organization dynamics in a mode-locked Mamyshev oscillator starting from coherent pulse seeds as opposed to quantum noise. We observed that the coherence of the seed can be remembered or forgotten during the mode-locking transition, depending on the initial inverse population. The excessive nonlinearity in the coherence amnesia regime can devastate the seed coherence, while this coherence is retained in the transition for the memory regime. A heterodyne technique was developed to record the fast varying optical phase and characterize these two transition pathways. Dissipative soliton molecules were synthesized from external pulse pair seeds via the coherence memory pathway. In this case, a plateau of the generated pulse spacing independent of seed pulse spacing was observed. Moreover, we show that pulse seeds can be used for laser reconfiguration and optical pulse buffering. Our work paves a way to control transient pulse dynamics and relative pulse timing on demand in mode-locked lasers.