Nonlinear Pulse Dynamics in Fiber Lasers at the Verge of Mode-Locking and in Transition Regimes

非技术描述：超短脉冲持续时间的激光器在精密测量、微机械加工、生物医学成像和医疗外科中得到了广泛的应用。对于这些领域中的任何一个，能够监测和预测功率和激光特性以避免过度的组织或材料损伤是至关重要的。由于这些激光器具有极短的脉冲持续时间(约为飞秒级)，超过了最快的电子表征仪器，因此现有的挑战是实时捕获脉冲到脉冲的演变。这项提议的目标是开发新的实时光学表征方法，能够洞察逐个脉冲的行为并表征新的激光状态。这些方法可以在通信系统中实现新的调制方案，同时对激光器的开发和优化产生根本影响。此外，所提出的实时表征方法可以为连续监测细胞机制、流体动力学或化学反应动力学提供强大的分析工具。该项目还提供了一个机会，在激光物理、系统工程、材料科学和实时表征的交叉点培养本科生和研究生，以建立新一代多方面的研究人员，以应对未来技术和社会挑战的跨学科性质。PI将通过波士顿范围内突出女性工程师的Photonics网络系列来组织专业网络和指导机会。其目的是将不同的工程师和科学家群体聚集在一起，并鼓励该领域中代表性不足的少数群体。技术描述：PI建议开发一种实时测量系统，以分析波长在2微米左右的掺Tm-Ho光纤激光器和波长在1.5微米范围内的掺铒光纤激光器中的脉冲间演化和相位相干性。该提案旨在探索和表征超快光纤激光器的逐个脉冲的瞬时效应、快速波动和非线性脉冲动力学，例如处于锁模边缘。一种基于色散傅里叶变换的改进的时间展宽技术将被开发来捕捉单脉冲尺度上的脉冲行为。旨在解决光纤中不同脉冲整形机制之间错综复杂的相互作用的系统研究将导致对脉冲动力学和暂态的基本认识，这些可用于设计新型激光腔、解决偏振演化和优化性能参数。

Title: Nonlinear Pulse Dynamics of Ultrafast Fiber Lasers in Transition Regimes Non-technical description: Lasers with ultrashort pulse durations have found widespread applications in precision measurements, micromachining, biomedical imaging and medical surgery. For any of these fields, it is crucial to be able to monitor and predict the power and laser properties to avoid excessive tissue or material damage. As these lasers feature extremely short pulse durations (on the order of femtoseconds) which exceed the fastest electronic characterization instruments, an existing challenge is to capture the pulse-to-pulse evolution in real-time. The goal of this proposal is to develop new real-time optical characterization methods that can provide insight into the pulse-by-pulse behavior and characterize novel lasers states. These methods can enable new modulation schemes in communication systems while having fundamental impact on laser development and optimization. In addition, the proposed real-time characterization methods can provide powerful analysis tools for continuous monitoring of cell mechanisms, fluid dynamics or chemical reaction kinetics. This project also provides an opportunity to train undergraduate and graduate students at the intersection of laser physics, systems engineering, materials science, and real-time characterization to build a new generation of multi-faceted researchers to tackle the interdisciplinary nature of technological and societal challenges in the future. The PI will organize professional networking and mentoring opportunities through a Boston-wide Photonics Networking series that highlights female engineers. This aims to bring together a diverse group of engineers and scientists and to encourage underrepresented minorities in the field. Technical description: The PI proposes to develop a real-time measurement system to analyze the pulse-to-pulse evolution simultaneously with phase coherence in thulium-holmium doped fiber lasers around 2 micron wavelengths as well as for erbium doped fiber lasers in 1.5 micron region. The proposal aims at exploring and characterizing transient effects, rapid fluctuations and nonlinear pulse dynamics on a pulse-by-pulse basis for ultrafast fiber lasers, e.g. at the verge of mode-locking. A modified time-stretching technique based on dispersive Fourier transform is to be developed to capture pulse behavior on a single pulse scale. Systematic studies aimed at resolving the intricate interplay between different pulse shaping mechanisms in fibers will lead to fundamental insights into pulse dynamics and transient states that can be applied to design novel laser cavities, resolve polarization evolution and optimize performance parameters.