Multi-port real-time observation for ultrafast intracavitary evolution dynamics

Abstract

Recent advance of real-time spectral measurements offers a promising route for revealing the underlying mechanisms of transient phenomena, and successfully provides direct experimental evidence for soliton-related theoretical predictions. However, as current real-time spectrum measurement focuses on the single-port observation of laser, the continuous evolution intracavitary process with short duration cannot be fully and truly characterized. To alleviate this restriction, we present a new conceptual approach for the intracavitary process, where spectra from multi-ports of a mode-locked fiber laser are collected in time division multiplexed sequence to realize synchronous real-time observation. The sinusoidal evolution of spectral beating process caused by the non-equilibrium state between intracavitary nonlinear devices is clearly observed and matched well with the simulation. Furthermore, the intracavitary evolutions of Kelly sidebands and peaks induced by self-phase modulation are obvious asynchronous with the soliton. This work may open up possibilities for real-time observation of various intracavitary nonlinear dynamics in photonic systems.