AI 中文总结
本研究提出一种基于增益开关自注入锁定DFB激光二极管的微波光子振荡器方案，通过匹配调制频率三次谐波与微谐振器自由光谱范围，实现platicon拍频相位噪声降低超30 dB，为微波合成提供稳健方法。
AI 中文摘要
利用光频微梳的集成光子器件已成为现代光子系统的核心工具，因其具备芯片级尺寸、高能量效率及固有稳定性而备受青睐。本研究提出一种基于增益开关自注入锁定分布式反馈（DFB）激光二极管产生克尔 platicon 微梳的新型微波光子振荡器方案。该系统通过直接调制激光二极管的电流，在泵浦线周围产生光边带；克尔梳齿与调制泵浦边带在高速光电探测器处的拍频，可获得可调谐、低噪声的微波信号，其频率接近 platicon 重复率，且远高于增益开关所用频率。实验中，通过扫描调制频率，我们实现了微波信号从100 MHz到3.6 GHz的连续调谐，该调谐源于生成边带相对于 platicon 拍频的偏移。我们将增益开关信号调制频率的三次谐波与微谐振器的自由光谱范围匹配，同时生成 platicon 微梳，这使得 platicon 拍频的频谱得到显著纯化，其相位噪声降低超过30 dB。所提出的新型架构为微波合成提供了一种稳健且通用的方法，对集成微波光子系统及其在通信、传感和计量学中的应用具有重要推进潜力。
英文摘要
Integrated photonic devices leveraging optical frequency microcombs have emerged as essential instruments for modern photonic systems, prized for their chip-scale footprint, high energy efficiency, and inherent stability. This work introduces a novel approach to microwave photonic oscillator based on generation of a Kerr platicon microcomb by a gain-switched self-injection-locked distributed feedback (DFB) laser diode. The system leverages direct modulation of the current of the laser diode, generating optical sidebands around the pump line. The beatnote between the Kerr comb lines and sidebands of the modulated pump at a high-speed photodetector allows to obtain tunable, low-noise microwave signals at frequencies close to the platicon repetition rate, which is many times higher than used for gain switching. We experimentally demonstrate continuous microwave signal frequency tuning from 100 MHz to 3.6 GHz by sweeping the modulation frequency, thereby shifting the generated sidebands relative to a platicon beatnote. We match third harmonics of the modulation frequency of the gain-switch signal with the free spectral range of the microresonator simultaneously generating the platicon microcomb. That leads to significant spectral purification of the platicon beatnote decreasing its phase noise by more than 30 dB. The novel architecture proposed offers a robust and versatile method for microwave synthesis, presenting significant potential for the advancement of integrated microwave photonic systems and their applications in communications, sensing, and metrology.
