Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages
Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages
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DOI：
10.1038/s41586-018-0551-y
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发表时间：
2018-10-04
期刊：
影响因子：
64.8
通讯作者：
Loncar, Marko
中科院分区：
文献类型：
--
作者：
Wang, Cheng;Zhang, Mian;Loncar, Marko
电光调制器将高速电子信号转换到光域，并且是现代电信网络（1，2）和微波光子系统（3，4）中的关键部件。它们也有望成为新兴应用的基石，如量子光子学（5，6）和非互易光学（7，8）。所有这些应用都需要芯片级电光调制器，这些调制器在与互补金属氧化物半导体（CMOS）技术兼容的电压下工作，具有超高的电光带宽并且具有非常低的光损耗。基于诸如硅、磷化铟或聚合物的材料的集成调制器平台由于所使用的材料的固有限制而尚不能同时满足这些要求。另一方面，几十年来光电工业的主力军-钛酸锂电光调制器（9）由于在微结构化钛酸锂方面的困难而在芯片上集成一直具有挑战性。当前一代的锂酸盐调制器体积大、价格昂贵、带宽有限并且需要高驱动电压，因此不能达到材料的全部潜力。在这里，我们克服了这些限制，并展示了单片集成的锂酸盐电光调制器，具有CMOS兼容的驱动电压，支持高达210千兆比特每秒的数据速率，并显示小于0.5分贝的片上光损耗。我们通过设计微波和光子电路来实现这一目标，以同时实现高电光效率，超低光损耗和群速度匹配。我们的可扩展调制器器件可为下一代光通信网络和微波光子系统提供经济高效、低功耗和超高速的解决方案。此外，我们的方法可以导致大规模的超低损耗光子电路，可在皮秒时间尺度上重新配置，从而实现广泛的量子和经典应用（5，10，11），包括前馈光子量子计算。
Electro-optic modulators translate high-speed electronic signals into the optical domain and are critical components in modern telecommunication networks(1,2) and microwave-photonic systems(3,4). They are also expected to be building blocks for emerging applications such as quantum photonics(5,6) and non-reciprocal optics(7,8). All of these applications require chip-scale electro-optic modulators that operate at voltages compatible with complementary metal-oxide-semiconductor (CMOS) technology, have ultrahigh electro-optic bandwidths and feature very low optical losses. Integrated modulator platforms based on materials such as silicon, indium phosphide or polymers have not yet been able to meet these requirements simultaneously because of the intrinsic limitations of the materials used. On the other hand, lithium niobate electro-optic modulators, the workhorse of the optoelectronic industry for decades(9), have been challenging to integrate on-chip because of difficulties in microstructuring lithium niobate. The current generation of lithium niobate modulators are bulky, expensive, limited in bandwidth and require high drive voltages, and thus are unable to reach the full potential of the material. Here we overcome these limitations and demonstrate monolithically integrated lithium niobate electro-optic modulators that feature a CMOS-compatible drive voltage, support data rates up to 210 gigabits per second and show an on-chip optical loss of less than 0.5 decibels. We achieve this by engineering the microwave and photonic circuits to achieve high electro-optical efficiencies, ultra-low optical losses and group-velocity matching simultaneously. Our scalable modulator devices could provide cost-effective, low-power and ultra-high-speed solutions for next-generation optical communication networks and microwave photonic systems. Furthermore, our approach could lead to large-scale ultra-low-loss photonic circuits that are reconfigurable on a picosecond timescale, enabling a wide range of quantum and classical applications(5,10,11) including feed-forward photonic quantum computation.