Optical resonators with controllable $Q$ factors are key components in many areas of optical physics and engineering. We propose and investigate a $Q$-factor controllable system composed of two directly coupled microring resonators, one of which is tunable and coupled to dual waveguides. By shifting the resonance of the controllable microring, the $Q$ factor of the system as well as the other microring changes significantly. We have demonstrated wide-range controllable $Q$ factors based on this structure in silicon-on-insulator, for example. The influences of spectral detuning and coupling strength between two resonators on the variation of $Q$ factors are studied in detail experimentally. Then, we explore its applications in optical buffering. Tunable fast-to-slow/slow-to-fast light has been carried out by switching the system between the high-$Q$ state and low-$Q$ state. Moreover, optical pulse capture and release are also achievable using this structure with dynamic tuning, and the photon storage properties are investigated. The proposed $Q$-factor tunable system is simple, flexible, and realizable in various integrated photonic platforms, allowing for potential applications in on-chip optical communications and quantum information processing.

中文翻译：

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用于光缓冲应用的直接耦合微环谐振器中可控 Q 因子的提议和演示

可控光谐振器 $问$因子是光学物理和工程许多领域的关键组成部分。我们提出并调查一个$问$-因子可控系统由两个直接耦合的微环谐振器组成，其中一个是可调的并耦合到双波导。通过改变可控微环的共振，$问$系统的因子以及其他微环显着变化。我们已经展示了广泛的可控性$问$例如，基于绝缘体上硅结构的因素。两个谐振腔之间的频谱失谐和耦合强度对谐振频率变化的影响$问$因素进行了详细的实验研究。然后，我们探索它在光缓冲中的应用。可调谐快到慢/慢到快光已通过在高-$问$ 状态和低$问$状态。此外，使用这种具有动态调谐的结构也可以实现光脉冲捕获和释放，并研究了光子存储特性。拟议的$问$因子可调系统简单、灵活，可在各种集成光子平台中实现，在片上光通信和量子信息处理中具有潜在应用。