提出了一种基于耦合射频(RF)信号和单个马赫-曾德尔调制器(MZM)的可调光学频率梳(OFC)产生方案,采用低成本的耦合射频信号替代高成本的高频信号源,降低了产生装置的成本。同时建立了不同耦合射频信号驱动MZM产生OFC的理论模型,对方案进行了理论分析,并利用软件OptiSystem 13.0仿真研究了MZM的上、下支臂调制电压、射频信号源输出频率和耦合方式对OFC的梳线数目、功率平坦度及频率间隔的影响。仿真结果表明,当射频信号源输出频率为5 GHz、乘法耦合次数为4时,可得到频率间隔为10 GHz、梳线数目为7、功率平坦度为1.88 dB的OFC。与基于单个MZM的同频率间隔OFC产生方案相比较,本方案产生的频率分量数目较多、平坦度较高且成本低,对低成本、高性能光学频率梳的产生具有一定的指导意义。

A scheme to generate a tunable optical frequency comb (OFC) based on coupled radio frequency (RF) signals and Mach-Zehnder modulator (MZM) is proposed. The coupled RF signal generated using a cheap signal source can be used to replace the expensive and high-frequency signal sources, thereby reducing the cost of OFC generators. The theoretical model of OFC generated using various coupled RF signals is established, and the scheme is verified using OptiSystem 13.0. The effects of the modulating voltages of upper and lower arms of MZM, output frequency of the RF signal source, and coupling mode on the comb number, power flatness, and frequency interval are analyzed. Simulation results indicate that for 5-GHz output RF signal and 4 times multiplicative-couple, OFC with frequency interval of 10 GHz, comb line number of 7, and power flatness of 1.88 dB can be obtained. Moreover, the proposed scheme can generate OFC with additional comb-lines, better flatness, and lower cost compared with the same frequency interval OFC generation scheme based on a single MZM. The proposed scheme provides guiding significance for the design of low-cost and high-performance OFC generators.