Electro-optic modulators with low voltages and large bandwidths are crucial for both analog and digital communication. Recently, thin-film lithium niobate modulators have emerged as a strong candidate for next generation electro-optic solutions. These modulators offer significantly improved voltage–bandwidth performances over the existing bulk lithium niobate modulators while preserving key material advantages such as linear response, high extinction ratio, high optical power handling ability, and low optical losses. However, reduced electrode gaps in miniaturized thin-film modulators lead to higher microwave losses, which limit electro-optic performances at high frequencies. Here we overcome this limitation to achieve a record combination of low RF half-wave voltage (${V_\pi}$) of 1.3 V while maintaining electro-optic response with 1.8 dB roll-off at 50 GHz using micro-structured electrodes. Our demonstration represents a significant improvement in voltage–bandwidth performance, one that is comparable to the performance gain in switching from legacy bulk to thin-film lithium niobate modulators. Such a micro-structured electrode design could enable sub-volt modulators with ${\gt}\! 100\;{\rm GHz}$ bandwidth.

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使用微结构电极的集成铌酸锂调制器突破了电压带宽限制

低压和大带宽的电光调制器对于模拟和数字通信都至关重要。最近，薄膜铌酸锂调制器已成为下一代电光解决方案的强大候选者。这些调制器与现有的块状铌酸锂调制器相比，具有明显改善的电压带宽性能，同时保留了关键的材料优势，例如线性响应，高消光比，高光功率处理能力和低光损耗。但是，缩小的薄膜调制器中的电极间隙会导致更高的微波损耗，这会限制高频下的电光性能。在这里，我们克服了这一限制，以实现低射频半波电压（$ {V_ \ pi} $）（1.3 V），同时使用微结构化电极在50 GHz下保持1.8 dB滚降的电光响应。我们的演示代表了电压带宽性能的显着改善，这与从传统的大体积铌酸锂薄膜调制器切换到薄膜铌酸钡调制器时的性能提升相当。这种微结构化的电极设计可以使具有$ {\ gt} \！的亚伏特调制器成为可能。100 \; {\ rm GHz} $带宽。