State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2018 May 9;9(1):1839. doi: 10.1038/s41467-018-04240-6.
An optoelectronic oscillator (OEO) is a microwave photonic system with a positive feedback loop used to create microwave oscillation with ultra-low phase noise thanks to the employment of a high-quality-factor energy storage element, such as a fiber delay line. For many applications, a frequency-tunable microwave signal or waveform, such as a linearly chirped microwave waveform (LCMW), is also needed. Due to the long characteristic time constant required for building up stable oscillation at an oscillation mode, it is impossible to generate an LCMW with a large chirp rate using a conventional frequency-tunable OEO. In this study, we propose and demonstrate a new scheme to generate a large chirp-rate LCMW based on Fourier domain mode locking technique to break the limitation of mode building time in an OEO. An LCMW with a high chirp rate of 0.34 GHz/μs and a large time-bandwidth product of 166,650 is demonstrated.
光电子振荡器（OEO）是一种带有正反馈回路的微波光子系统，由于采用了高品质因数储能元件（如光纤延迟线），可产生超低相位噪声的微波振荡。对于许多应用来说，还需要可调谐的微波信号或波形，例如线性啁啾微波波形（LCMW）。由于在振荡模式下建立稳定振荡所需的特征时间常数较长，因此使用传统的可调谐 OEO 无法产生具有大啁啾率的 LCMW。在本研究中，我们提出并展示了一种基于傅里叶域锁模技术的新方案，以打破 OEO 中模式建立时间的限制，从而生成具有大啁啾率的 LCMW。我们演示了一种具有 0.34GHz/μs 高啁啾率和 166650 大时带宽积的 LCMW。
