【摘要】 光纤时频传递技术具有高信噪比、高传递稳定度及强抗干扰能力等技术优势,然而,随着传输距离的增加,光纤链路引入的光学相位抖动不断增加,成为限制时频传递稳定度的主要因素。本文设计并实现了基于光程主动控制的延迟补偿系统,采用光纤环路光学-微波鉴相器获得了经往返传输的飞秒激光脉冲与本地微波信号源的相位误差,避免了直接光电转换探测过程引入的附加光电噪声,提高相位误差探测精度;采用压电式光纤拉伸快速反馈及电动光学延迟线慢反馈复合控制方式,实现链路延迟的长期自动实时补偿。实验结果显示,经11km光纤链路往复传递后的飞秒激光脉冲时间延迟补偿稳定度达到1.55fs/s与0.12fs/1 000s,对应频率稳定度达到3.06×10^-15/s与1.99×10^-19/1 000s。更多还原

【Abstract】 Time and frequency transfers through fiber links have advantages of high stability,high signal-to-noise ratio and anti-jamming capacity over the other techniques. As the path length increases,optical phase jitter introduced by fiber link dramatically increases. This phenomenon is the main limitation of the performance. Here we demonstrate an active optical path control system in a long fiber link. In this system,a fiber-loop optical-microwave phase detector is integrated to obtain the phase error between return optical femtosecond pulses from remote site and local clock reference. It avoids the intense phase noise caused by direct photoelectric detection,therefore improves the sensitivity of phase detection. Meanwhile,an optical fiber stretcher and motorized optical delay line are utilized and automatically controlled in real-time. The home-built active optical path control system is experimentally tested in a 11 km optical fiber link. The time deviations are 1. 55 fs/s and 0. 12 fs/1 000 s,respectively. Correspondingly,the frequency stabilities are 3. 06 × 10^-15/s and 1. 99 × 10^-19/1 000 s,respectively.更多还原