研究了一种由多个长光纤环构建的频率可调光电振荡器，多个组合的长光纤环能够降低光电振荡器的相位噪声和提高边模抑制比，保证了高性能微波信号的产生，通过高速的微波开关切换带通滤波器组能够产生不同的信号频率输出。在构建的工作于X波段的光电振荡器实验中，实现了频率为8、9、10、12 GHz的微波信号输出。对于产生的每个频率信号，输出功率均大于10 dBm，边模抑制比均大于60 dBc。在频率偏移10 kHz处，相位噪声达到了-130 dBc/Hz。实验结果与理论分析变化趋势一致，证明了该方法的正确性。

A new optoelectronic oscillator with switchable frequency and high performance, based on multiple long fiber loops, is demonstrated. This oscillator can simultaneously obtain low phase noise and high side mode suppression ratio, and provide different output frequencies by selecting narrow bandpass filters. In the experiment, the optoelectronic oscillator can operate at 8, 9, 10, 12 GHz by switching the filter frequency. For each frequency, the output power higher than 10 dBm and side mode suppression ratio more than 60 dBc can be realized. The phase noise lower than -130 dBc/Hz at 10 kHz offset can be obtained. The experimental results agree with the theoretical analysis, which proves the correctness of the method.