Li Dechen, Li Run, Li Mingxuan, Han Mengjie, Liu Jianguo, An Junming, Wang Suo, Li Jinye
Opt Express. 2025 Jul 28;33(15):31556-31566. doi: 10.1364/OE.564080.
Flat electro-optic frequency combs, as coherent spectral sequences with equidistant distribution, exhibit significant potential in high-capacity optical communication and reconfigurable microwave photonics. This study develops a monolithically integrated, fully packaged electro-optic comb device on a thin-film lithium niobate (TFLN) platform using an efficient photolithography scheme, overcoming the size and loss constraints of traditional discrete cascaded components. The synergistic interaction between cascaded amplitude modulator (AM) and three phase modulators (PMs) balances the optimization between comb-line count and flatness. Theoretical modeling reveals that flatness nonlinearly depends on intensity modulation parameters, while comb-line count linearly correlates with phase modulation coefficients. Experimentally, a coherent spectrum with 27 comb lines is generated, achieving 25 GHz equidistant spacing and 3 dB in-band flatness. Tests show a total insertion loss of 10.2 dB, an intrinsic 3 dB electro-optic bandwidth of 56 GHz, and high bias stability via integrated NiCr thermal resistors. Compared to conventional discrete-component schemes, this device achieves significant improvements in comb-line spacing expansion, power efficiency optimization, and system integration, offering a highly stable dynamic light source solution for high-speed optical communication and programmable photonic systems.
平面电光频率梳作为具有等距分布的相干光谱序列，在高容量光通信和可重构微波光子学中展现出巨大潜力。本研究利用高效光刻方案，在薄膜铌酸锂（TFLN）平台上开发了一种单片集成、全封装的电光梳状器件，克服了传统离散级联组件的尺寸和损耗限制。级联幅度调制器（AM）和三个相位调制器（PM）之间的协同相互作用平衡了梳状线数量和平坦度之间的优化。理论建模表明，平坦度非线性地依赖于强度调制参数，而梳状线数量与相位调制系数线性相关。实验上，产生了具有27条梳状线的相干光谱，实现了25 GHz的等距间距和3 dB的带内平坦度。测试显示总插入损耗为10.2 dB，固有3 dB电光带宽为56 GHz，并通过集成NiCr热敏电阻实现了高偏置稳定性。与传统离散组件方案相比，该器件在梳状线间距扩展、功率效率优化和系统集成方面取得了显著改进，为高速光通信和可编程光子系统提供了一种高度稳定的动态光源解决方案。
