Abstract
Recent research on nonlinear multimode interference (NL-MMI) based mode-locking method provides a new approach for ultrafast all-fiber lasers. Here, we report on the polarization dynamics of group velocity locked vector solitons (GVLVSs) and noise-like vector pulses (NLVPs) in a graded-index multimode fiber (GIMF) based all-fiber laser. Due to the non-polarization sensitive characteristic of the NL-MMI, emitted pulses automatically evolve into the vector multi-pulse complexes constituting two orthogonally polarized components. Beyond the traditional polarization resolved measurement, dispersive Fourier transform (DFT) and polarization beam splitting techniques are jointly adopted to enable insights into the transient polarization dynamics of the vector solitons. It is found in real time that the two orthogonally polarized components oppositely shift their central wavelengths to compensate the polarization dispersion. In addition, stationary and pulsating NLVPs are respectively unfolded by the DFT based polarization resolved measurement. Especially, the pulsating NLVPs before and after polarization resolved measurement are accompanied with the identical periodic spectral breathing process. All these findings reveal the vectorial nature in NL-MMI based ultrafast fiber lasers, as well as highlight the transient polarization dynamics and the long-term pulsation in dissipative systems.
Highlights
Ultrafast fiber lasers have been extensively studied for both providing the widespread applications in optical communications, micromachining, biomedicine, and serving as an experimental platform towards the exploration of nonlinear dynamics [1]–[4]
We report on the polarization dynamics of group velocity locked vector solitons (GVLVSs) and noise-like vector pulses (NLVPs) in a nonlinear multimode interference (NL-MMI) based allfiber laser
The two orthogonally polarized components of the GVLVSs are of stationary relations
Summary
Ultrafast fiber lasers have been extensively studied for both providing the widespread applications in optical communications, micromachining, biomedicine, and serving as an experimental platform towards the exploration of nonlinear dynamics [1]–[4]. The NL-MMI, interpreted as an equivalent fast saturable absorber (SA) can be utilized for ultrashort pulse generation with unprecedented energy in passively mode-locked fiber lasers. In order to circumvent this limitation, step-index multimode fiber (SIMF) [15] and non-core fiber (NCF) [16] were proposed to expand the diameter of mode field, optimizing the performance of the NL-MMI based mode-locking. Soliton molecules were observed in a fiber laser mode-locked by the hybrid structure of NCF-GIMF [16]. The temporal separation intra molecules can be flexibly controlled by stretching the mode-locking device. It can be seen that the NL-MMI based ultrafast fiber lasers can provide an optimal platform for investigating the profound soliton dynamics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
