RUI: Perturbation-Induced Dynamics and Chaos Synchronization in Multi-Transverse-Mode Vertical-Cavity Surface-Emitting Lasers

垂直腔面发射激光器（VCSEL）是一种对光反馈和光注入敏感的激光器，广泛应用于光通信和光纤互连领域。这些扰动可以诱发丰富的非线性动力学行为，如谱展宽、不规则和混沌脉动以及极化不稳定。当偏置电流增大时，VCSELs通常工作在多个横向模式下，不同横向模式的空间分布增加了系统的复杂性。因此，光注入和反馈引起的动力学是基础科学和工程应用领域的一个重要研究课题。其中，光反馈和光注入在双激光器混沌同步中起着关键作用，对数据通信安全具有重要意义。混沌同步也是耦合时滞系统的一个基本特性。实验研究了微扰诱导的VCSELs极化和横向动力学。在多横模系统中，我们研究了进入混沌系统的动态路径、光反馈与电流调制的相互作用以及两个频率的光注入效应。所得结果有助于实现两个多模vcsel的混沌同步，并验证了相应的理论结果。如上所述，VCSEL是研究复杂系统动态的理想载体，也是光纤通信中很有前途的设备。我们对受摄动影响的多横模VCSELs非线性动力学的研究将为研究非线性动力学和激光物理的科学家带来有趣的结果。由于多模vcsel具有较低的模态噪声和混沌同步对数据安全传输的重要性，因此该研究结果对光纤通信领域也有一定的参考价值。该项目通过将研究与本科训练和学习相结合来加强本科教育。学生通过暑期研究、毕业论文和独立研究参与项目。此外，还在高级课程和实验室中介绍了利用vcsel的实验和演示。当地的高中学生和教师可以通过参与研究和参观PI的实验室从该项目中受益。

Widely used in optic-fiber communications and interconnections, vertical-cavity surface-emitting lasers (VCSEL) are sensitive to optical feedback and optical injection. These perturbations can induce rich nonlinear dynamical behaviors, such as spectral broadening, irregular and chaotic pulsations, and polarization instabilities. Since VCSELs often operate with several transverse modes when the bias current goes up, complexity of the system increases due to spatial profiles of different transverse modes. Therefore dynamics induced by optical injection and feedback is a topic of significant research interests for both fundamental science and engineering applications. In particular, both optical feedback and optical injection play key roles in chaos synchronization of two lasers, which is of interest to secure data communications. Chaos synchronization is also a fundamental property of coupled, time-delay systems. We investigate experimentally perturbation-induced polarization and transverse dynamics of VCSELs. In the multi-transverse mode regime, we study dynamical routes to chaotic regime, interplay of optical feedback and current modulation, and effects of optical injection of two frequencies. The obtained results help us to achieve chaos synchronization of two multimode VCSELs and to validate corresponding theoretical results. As described above, a VCSEL is an ideal vehicle for studying dynamic in complex systems and a promising device in fiber-optic communications. Our study on nonlinear dynamics of multi-transverse-mode VCSELs subject to perturbations will produce interesting results for scientists who study nonlinear dynamics and laser physics. The results will also be useful to community of optic-fiber communications because multimode VCSELs have been used in local area network (LAN) due to their lower modal noise and because chaos synchronization is important for secure data transmission. The project enhances undergraduate education by integrating research with undergraduate training and learning. Students are involved in the project through summer research, senior theses, and independent studies. Besides, experiments and demonstrations that utilize VCSELs are introduced in advanced courses and laboratory. Local high school students and teachers can benefit from the project through joining the research and visiting the PI's laboratory.