Zeng Zhen, Zhang Lingjie, Zhang Yaowen, Tian Huan, Zhang Zhiyao, Zhang Shangjian, Li Heping, Liu Yong
Opt Lett. 2021 May 1;46(9):2107-2110. doi: 10.1364/OL.422556.
An actively mode-locked optoelectronic oscillator (OEO) is proposed and demonstrated to generate chirp-free microwave pulse trains with variable repetition rates. Time-domain mode locking is realized by using an electric signal modulator to achieve amplitude modulation of the generated microwave signal in the OEO cavity. Through setting the externally applied electric signal frequency to be equal to the integral multiple of the free spectral range, a microwave pulse train with a low close-to-carrier phase noise is generated. In the experiment, microwave pulse trains with repetition rates of 179.94 and 360.00 kHz are generated through fundamental mode locking and 2nd-order harmonic mode locking, respectively. Under fundamental mode locking, the phase noise of the actively mode-locked OEO at 100 Hz frequency offset is measured to be 30 dB lower than that in a free-running OEO.
提出并演示了一种主动锁模光电振荡器（OEO），用于产生具有可变重复率的无啁啾微波脉冲序列。通过使用电信号调制器实现OEO腔内所产生微波信号的幅度调制，从而实现时域锁模。通过将外部施加的电信号频率设置为自由谱范围的整数倍，产生了具有低载波附近相位噪声的微波脉冲序列。在实验中，分别通过基模锁模和二阶谐波锁模产生了重复率为179.94 kHz和360.00 kHz的微波脉冲序列。在基模锁模下，测得主动锁模OEO在100 Hz频率偏移处的相位噪声比自由运行的OEO低30 dB。
