Wang Jingyi, Wang Qi, Xu Mengyue, Zhu Yuntao, Wang Yanqun, Deng Huadi, Cai Xinlun
Opt Express. 2025 Jun 2;33(11):23431-23439. doi: 10.1364/OE.561993.
Electro-optic (EO) frequency combs offer distinct advantages, such as high flexibility in tuning the central wavelength and line spacing, insensitivity to input light power, and good spectral flatness, compared to other broadband microcombs and mode-locked lasers. EO combs are a perfect match for data communication requirements due to their lower power fluctuations per comb line and flexible frequency spacing. To date, flat EO combs demonstrate limited bandwidth and line numbers. Here, we present a Mach-Zehnder modulator cascade with three phase modulators with only a 3 V RF half-wave voltage at 25 GHz on a thin-film lithium niobate (TFLN) on silicon. The device is fabricated using a wafer-scale deep ultraviolet lithography process and is packaged with fiber pigtails and RF connectors for robust and stable testing. The TFLN-based packaged frequency comb generator produces 148 comb lines at a 25-GHz repetition rate with a power variation of 10 dB. The central wavelength is tuned to enable the frequency comb to cover the S, C, L, and U bands.
与其他宽带微梳和锁模激光器相比，电光（EO）频率梳具有显著优势，例如在调谐中心波长和线间距方面具有高度灵活性、对输入光功率不敏感以及良好的光谱平坦度。由于每条梳状线的功率波动较低且频率间距灵活，EO梳非常适合数据通信需求。到目前为止，平坦的EO梳带宽和线数有限。在此，我们展示了一种马赫曾德尔调制器级联结构，它带有三个相位调制器，在硅基薄膜铌酸锂（TFLN）上，在25GHz频率下仅需3V的射频半波电压。该器件采用晶圆级深紫外光刻工艺制造，并通过光纤尾纤和射频连接器进行封装，以便进行可靠且稳定的测试。基于TFLN的封装频率梳发生器以25GHz的重复频率产生148条梳状线，功率变化为10dB。通过调谐中心波长，使频率梳能够覆盖S、C、L和U波段。
