Xu Xingyuan, Dai Jian, Dai Yitang, Yin Feifei, Zhou Yue, Li Jianqiang, Yin Jie, Wang Qunyang, Xu Kun
Opt Lett. 2015 Dec 15;40(24):5858-61. doi: 10.1364/OL.40.005858.
In this Letter, we propose and experimentally demonstrate a novel broadband and wide-range feedback tuning scheme for phase-locked loop (PLL) stabilization of tunable optoelectronic oscillators (OEO). The proposed scheme was realized in a simple and feasible way based on a dual-parallel Mach-Zehnder modulator (DPMZM) and optical bandpass filter (OBPF). The wide RF phase-shift range and broadband performance of the proposed scheme were demonstrated theoretically and experimentally, which ensured OEO's wide operating temperature range and tunability in PLL stabilization. As a result, PLL stabilization for OEO was achieved at different oscillating frequencies and the long-term stability was greatly improved without any thermal control. The measured overlapping Allan deviation of PLL-locked OEO reached lower than 10⁻¹⁰ after 1000-s averaging time, which was four orders of magnitude better than the free-running OEO. The phase noise performance was also improved at low-offset frequencies and remained the same at high-offset frequencies.
在本信函中，我们提出并通过实验证明了一种用于可调谐光电子振荡器（OEO）锁相环（PLL）稳定的新型宽带和宽范围反馈调谐方案。所提出的方案基于双并行马赫曾德尔调制器（DPMZM）和光学带通滤波器（OBPF）以简单可行的方式实现。从理论和实验上证明了该方案具有宽射频相移范围和宽带性能，这确保了OEO在PLL稳定中的宽工作温度范围和可调性。结果，在不同振荡频率下实现了OEO的PLL稳定，并且无需任何热控制即可大大提高长期稳定性。在1000秒平均时间后，锁相环锁定的OEO的测量重叠阿伦偏差低于10⁻¹⁰，比自由运行的OEO好四个数量级。在低偏移频率下相位噪声性能也得到改善，在高偏移频率下保持不变。
