We investigate the mechanisms to realize the Raman laser switching in a silica rod microresonator with mode-interaction-assisted excitation. The laser switching can be triggered between two whispering gallery modes (WGMs) with either the same or distinct mode families, depending on the pumping conditions. The experimental observations are in excellent agreement with a theoretical analysis based on coupled-mode equations with intermodal interaction terms involved. Additionally, we also demonstrate switching of a single-mode Raman laser and a wideband spectral tuning range up to ∼32.67nm by selective excitation of distinct mode sequences. The results contribute to the understanding of Raman lasing formation dynamics via interaction with transverse mode sequences and may extend the microcavity-based Raman microlasers to potential areas in switchable light sources, optical memories, and high sensitivity sensors.

为了在基于回音壁模式光学微腔的光学频率梳生成中优化微腔的性能和光频梳的质量，对氟化镁晶体微腔的色散调控进行研究。首先，理论仿真研究了MgF₂晶体微腔边缘形状对腔内模场和总色散的影响；接着根据仿真结果实际加工了两种面形的MgF₂晶体微腔，分别为边缘平面型和单边楔形；然后，搭建了微腔性能检测系统和晶体微腔光梳生成系统，实测加工出的MgF₂晶体微腔样品的品质因子（Q值）最高可达1.1×108；最后在加工的两种面形晶体腔中均有效激发了超过200 nm的宽光谱范围的克尔光频梳。实验结果验证了边缘楔形的微腔结构确实能够有效压缩模场并调控总色散，相比于边缘平面型的微腔能够产生更宽光谱范围的光梳。

回音壁模式光学微腔是一种研究非线性光学现象的理想平台。在1 550 nm波段下成功实现了在CaF₂晶体微腔中产生五阶级联的受激布里渊散射激光。所用的CaF₂晶体微腔直径为12.6 mm，同时有着超高的品质因子，最高可以达到1.16×108。实验中发现，当大尺寸晶体腔与绝热的锥形光纤进行耦合时，能够激发出多个谐振模式，保证了能够方便地选择不同的谐振波长来匹配受激布里渊散射频移。可以消除在匹配微腔的自由频谱范围和布里渊频移时对微腔尺寸精准控制的需要。为了解决在微腔和波导耦合时的环境震动影响，还设计了一个可以精密耦合调节的封装平台，可以保证谐振腔和波导稳定的在氮气保护气体氛围中被耦合密封起来。产生的级联布里渊激光和设计出的稳定封装平台可以用于后续的应用开发，例如多波长布里渊激光器产生和基于布里渊激光的陀螺仪研发等。

In this Letter, we demonstrate high-quality (Q), millimeter-size, and V-shaped calcium fluoride crystalline resonators for modal modification. To manufacture such resonators, we develop a home-made machining system and explore a detailed process. With a dedicated polished container, three special polishing steps, including grinding, smoothing, and polishing, are employed to achieve the required surface smoothness, which is characterized by less than 3 nm. An ultra-high-Q factor exceeding 10⁸ is obtained by a coupled tapered fiber. In addition, a customized packaged structure for our disk resonator is achieved. The Q maintenance and stable spectrum are realized by sealing the coupling system in a hard disk. The simple, stable, portable, controlled, and integratable device would provide great potential in optical filters, sensors, nonlinear optics, cavity quantum electrodynamics, and especially some applications that require large resonators such as gyroscopes.