全光纤全正常色散铥玛姆舍夫振荡器中的自启动动力学
Self-starting Dynamics in All-fibre All-Normal-Dispersion Thulium Mamyshev oscillator
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中文总结 AI 辅助
本研究实现了首个1.9μm附近自启动全光纤全正常色散掺铥玛姆舍夫振荡器，揭示其脉冲建立路径，为开发紧凑稳健的短波红外光源提供了关键方案。
中文摘要 AI 辅助
噪声产生的超短脉冲形成是非线性耗散系统中的基本自组织过程，仍是超快光子学的核心内容。玛姆舍夫振荡器因不依赖传统可饱和吸收体，成为研究该现象的极具价值的平台，其脉冲形成由正常色散光纤中的自相位调制结合周期性偏移光谱滤波控制。在这类系统中实现自启动脉冲形成颇具挑战，尤其在较长波长下，受限于正常色散元件和复杂的增益动力学。本研究报道了据当前认知首个在1.9μm附近工作的自启动、全光纤、全正常色散掺铥玛姆舍夫振荡器。该腔采用紧凑的法布里-珀罗设计，包含色散工程掺铥增益光纤、高非线性无源正常色散光纤，以及一对无啁啾宽带光纤布拉格光栅。该振荡器无需外部注入或主动调制即可自启动，并在基腔重复频率下稳定噪声类脉冲产生机制。实时测量和数值模拟揭示了从噪声经瞬态多脉冲、脉冲竞争到稳定噪声类包络的建立路径。研究结果表明，定制的激光元件和增益介质特有的动力学对实现玛姆舍夫振荡器中的自启动超短脉冲形成，以及将这些激光概念扩展至近红外以外波段至关重要，从而推动紧凑且稳健的短波红外（SWIR）光源及超快自组织新机制的发展。
英文摘要
Ultrashort pulse formation from noise represents a fundamental self-organisation process in nonlinear dissipative systems and remains central to ultrafast photonics. Mamyshev oscillators offer a particularly valuable platform for investigating this phenomenon because they do not rely on conventional saturable absorbers. Instead, pulse formation is governed by self-phase modulation in normal-dispersion fibres combined with periodic offset spectral filtering. Achieving self-starting pulse formation in these systems is challenging, particularly at longer wavelengths, due to limited normal-dispersion components and the complex gain dynamics. This work reports, to the best of current knowledge, the first self-starting, all-fibre, all-normal-dispersion Thulium-doped Mamyshev oscillator operating near 1.9um. The cavity employs a compact Fabry-Perot design incorporating a dispersion-engineered Thulium-doped gain fibre, a highly nonlinear passive normal-dispersion fibre, and a pair of chirp-free broadband fibre Bragg gratings. The oscillator self-starts without external seeding or active modulation and stabilises noise-like pulse generation regime at a fundamental cavity repetition rate. Real-time measurements and numerical simulations reveal the build-up pathway from noise through transient multi-pulsing and pulse competition to a stationary noise-like envelope. Our results show that both tailored laser components and gain-medium-specific dynamics are essential for enabling self-starting ultrashort pulse generation in Mamyshev oscillators and for extending these laser concepts beyond the near-infrared, thereby facilitating the development of compact and robust shortwave infrared (SWIR) sources and new regimes of ultrafast self-organisation.
