多射频信号驱动光相位调制器产生光学频率梳

Multiple radio frequency signals drive optical phase modulators to generate optical frequency combs

摘要:

针对传统光频梳产生系统结构复杂、控制难度大的问题，设计了一种基于单相位调制器的光频梳产生方案。利用两路射频信号混频驱动相位调制器，仅通过调整调制指数和射频信号相移，即可获得多梳线、高平坦性光频梳。建立了方案的理论模型，仿真研究了调制指数、射频信号相移和梳线间距对光频梳平坦度的影响，最后进行了实验验证。结果表明理论研究、仿真分析与实验结果三者较为吻合，当两路射频信号的频率分别为f1和2f1、移相器相移为45°、调制指数为1.431时，可以获得谱线间距为f1、平坦度为0.8dB、谱线数为9条的光频梳，其功率效率可达79.91%。

Abstract:

To overcome the challenges of complex structure and control in traditional optical frequency comb generation, a novel scheme based on a single-phase modulator was proposed. By driving a phase modulator with two mixed RF signals, multiple comb lines and high flatness optical frequency combs could be obtained by adjusting only the modulation index and RF signal phase shift. A theoretical model of the scheme was established, and simulations were conducted to investigate the effects of the modulation index, RF signal phase shift, and comb line spacing on the flatness of the optical frequency comb. Experimental validation was subsequently performed. The results demonstrate a good agreement among theoretical studies, simulation analyses, and experimental outcomes. Specifically, when the frequencies of the two RF signals are set to f? and 2f?, the phase shift of the phase shifter is 45°, and the modulation index is 1.431, an optical frequency comb with a f? line spacing, a 0.8 dB flatness, and 9 comb lines is obtained, achieving a power efficiency of up to 79.91%.