Lin XiaoDong, Xia GuangQiong, Shang Zhou, Deng Tao, Tang Xi, Fan Li, Gao ZiYe, Wu ZhengMao
Opt Express. 2019 Jan 21;27(2):1217-1225. doi: 10.1364/OE.27.001217.
Based on the period-one (P1) dynamics of an optically injected semiconductor laser (SL), a photonic scheme enabling the generation of a tunable high-quality frequency-modulated continuous-wave (FMCW) signal is investigated experimentally. Under a modulated optical injection, the laser is driven into P1 oscillation with a modulated microwave frequency. In this work, optical feedback is also introduced to further reduce the microwave phase noise. The experimental results show that the central frequency of the generated FMCW signal can be widely tuned from 11.41 to 50.05 GHz by simply adjusting injection parameters while the frequency sweep range of the FMCW signal can be controlled by varying the modulation index. Under proper operating parameters, the sweep range and rate of the FMCW signal are 18.42 GHz (13.73 GHz- 32.15 GHz) and 1.14 GHz/ns, respectively. Further, by introducing an optical feedback loop, the frequency comb contrast of the FMCW signal is drastically increased by 27.15 dB when the reciprocal of the feedback delay time matches with the modulation frequency exactly due to the locking effect of the external cavity optical modes.
基于光注入半导体激光器（SL）的一阶（P1）动力学，对一种能够产生可调谐高质量调频连续波（FMCW）信号的光子方案进行了实验研究。在调制光注入下，激光器被驱动到具有调制微波频率的P1振荡状态。在这项工作中，还引入了光反馈以进一步降低微波相位噪声。实验结果表明，通过简单地调整注入参数，所产生的FMCW信号的中心频率可以在11.41至50.05GHz范围内进行广泛调谐，而FMCW信号的扫频范围可以通过改变调制指数来控制。在适当的工作参数下，FMCW信号的扫频范围和速率分别为18.42GHz（13.73GHz - 32.15GHz）和1.14GHz/ns。此外，通过引入光反馈回路，当反馈延迟时间的倒数与调制频率精确匹配时，由于外腔光学模式的锁定效应，FMCW信号的频率梳对比度大幅提高了27.15dB。
