• Advanced Photonics
  • Vol. 1, Issue 1, 016003 (2019)
Xueming Liu1、2、3、* and Yudong Cui1
Author Affiliations
  • 1Zhejiang University, College of Optical Science and Engineering, State Key Laboratory of Modern Optical Instrumentation, Hangzhou, China
  • 2Nanjing University of Aeronautics and Astronautics, Institute for Advanced Interdisciplinary Research, Nanjing, China
  • 3Hunan University of Science and Technology, School of Physics and Electronic Science, Xiangtan, China
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    Abstract

    Real-time spectroscopy based on an emerging time-stretch technique can map the spectral information of optical waves into the time domain, opening several fascinating explorations of nonlinear dynamics in mode-locked lasers. However, the self-starting process of mode-locked lasers is quite sensitive to environmental perturbation, which causes the transient behaviors of lasers to deviate from the true buildup process of solitons. We optimize the laser system to improve its stability, which suppresses the Q-switched lasing induced by environmental perturbation. We, therefore, demonstrate the first observation of the entire buildup process of solitons in a mode-locked laser, revealing two possible pathways to generate the temporal solitons. One pathway includes the dynamics of raised relaxation oscillation, quasimode-locking stage, spectral beating behavior, and finally the stable single-soliton mode-locking. The other pathway contains, however, an extra transient bound-state stage before the final single-pulse mode-locking operation. Moreover, we propose a theoretical model to predict the buildup time of solitons, which agrees well with the experimental results. Our findings can bring real-time insights into ultrafast fiber laser design and optimization, as well as promote the application of fiber laser.

    1 Introduction

    Transient phenomena and dynamics are important characteristics of numerous nonlinear systems.17 Solitons are localized formations in nonlinear systems,815 appearing in many nonlinear processes, from fluid and biology dynamics, to plasma physics and fiber lasers,1619 and especially in mode-locked lasers.5,11,20 The mode-locked fiber laser, as an ideal platform, is used for exploring nonlinear phenomena due to its compact and low-cost configuration as well as excellent features of high stability and low noise. Solitons observed in mode-locked lasers exhibit several special behaviors, such as soliton bunching and soliton bounding (i.e., the generation of soliton molecules).2123

    Copy Citation Text
    Xueming Liu, Yudong Cui. Revealing the behavior of soliton buildup in a mode-locked laser[J]. Advanced Photonics, 2019, 1(1): 016003
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    Category: Research Articles
    Received: Oct. 22, 2018
    Accepted: Dec. 25, 2018
    Published Online: Feb. 18, 2019
    The Author Email: Liu Xueming (liuxueming72@yahoo.com)