提出了一种基于中频相位锁定技术提升宽带调谐光电振荡器长期稳定性的方法.该方法通过外部可调本振源对光电振荡器射频信号进行下变频操作, 产生中频信号, 该中频信号与光电振荡器的起振频率无关.将该中频信号锁相在稳定的参考源上, 能够提升宽带调谐光电振荡器的长期稳定性, 同时分析了锁相环对光电振荡器相位噪声性能的影响.实验结果显示, 光电振荡器的频率调谐范围可达5~15 GHz, 10 kHz频偏处的相位噪声为－121.2 dBc/Hz, 频率稳定性达到6.9×10－11/103 s, 表明该方法能够显著提升宽带调谐光电振荡器的稳定性.

A scheme for improving the long-term stability of a wideband tunable optoelectronic oscillator based on intermediate frequency phase-locked loop technique is proposed. In the scheme, an external tunable local oscillator is used to down-convert the RF signal of the optoelectronic oscillator to generate an intermediate frequency signal, which is independent of the oscillating frequency of the optoelectronic oscillator. Phase-locking of the intermediate frequency signal to a stable reference source can improve the long-term stability of the wideband tuanble optoelectronic oscillator. The impact of the phase-locked loop on the phase noise performance of the optoelectronic oscillator is also analyzed. Experimental results show that the frequency tuning range of the optoelectronic oscillator is 5~15 GHz, the phase noise is －121.2 dBc/Hz at 10 kHz offset and the long-term stability is 6.9×10－11/103 s. It indicates that the proposed method can significantly improve the long-term stability of a wideband tunable optoelectronic oscillator.