为了探寻一种基于光频梳的灵活、高效的多频段变频方案, 采用一个双驱动马赫-曾德尔调制器(D-MZM)和两个双平行马赫-曾德尔调制器(DP-MZM)组成的系统, 由接收到的射频信号驱动D-MZM, 进行单边带调制, 进而得到一个载波和+1阶边带。利用两个DP-MZM分别作为两个光频梳产生器, 产生两个相位相干、中心频率不同的光频梳, 并进行了理论分析和实验验证; 同时还研究了直流偏置点漂移对系统变频效率的影响。结果表明, 所提出的变频系统, 可将Ku波段的15GHz微波信号转化成3GHz, 7GHz, 11GHz, 19GHz, 23GHz和27GHz的信号; 输出的微波信号信噪比可达28.82dB~29.99dB; 直流偏置点的漂移量在-10%～50%范围内影响明显。该方法可为卫星通信系统提供多频段变频功能, 从而满足多频段通信需求。

In order to explore a flexible and efficient multiband frequency conversion scheme based on optical frequency comb, a system consisting of one dual-drive Mach-Zehnder modulator (D-MZM) and two double-parallel Mach-Zehnder modulators (DP-MZM) was used. D-MZM was drived by the received radio frequency signal, single side band modulation was carried out and then one carrier and +1 order side band were obtained. Two DP-MZMs were used as two optical comb generators, and two optical frequency combs with different phase coherence and different center frequencies were produced. The influence of DC bias point drift on frequency conversion efficiency of the system was also studied. After theoretical analysis and experimental verification, the results show that the proposed frequency conversion system can convert 15GHz microwave signals in Ku band into 3GHz, 7GHz, 11GHz, 19GHz, 23GHz and 27GHz. The signal-to-noise ratio of output microwave signal can reach 28.82dB~29.99dB. The drift of DC bias point is within the range of -10% to 50%. The influence is obvious. This method can provide multiband frequency conversion for a satellite communication system to meet requirements of multiband communication.