Author: Jian Shen, Yong Zhang*, Lei Zhang, Jingchi Li, Chenglong Feng, Yongheng Jiang, Hongwei Wang, Xingfeng Li, Yu He, Xingchen Ji, Guofeng Yin, Yonghui Tian, Xi Xiao, and Yikai Su*
Abstarct: High-speed electro-optic modulators are key components in modern communication networks and various applications that require chip-scale modulation with large bandwidth, high modulation efficiency, and compact footprint. However, fundamental trade-offs make it challenging to achieve these metrics simultaneously, and thus new methodologies must be explored. To this end, a Mach–Zehnder modulator harnessing slow-light waveguides and capacitively loaded slow-wave electrodes are presented on silicon-nitride-loaded lithium niobate on an insulator platform. The increased group index and reduced microwave loss significantly improve the modulation efficiency. With the 1-mm-length modulation section, a low half-wave voltage length product Vπ·L of 0.21 V cm is obtained, which is one order of magnitude smaller than that of conventional thin film lithium niobate Mach–Zehnder modulators, and a modulation bandwidth of surpassing 110 GHz is achieved. The digital signal processor-free non-return-to-zero signal and eight-level pulse amplitude modulation signal of up to 180 and 300 Gbps, respectively, are generated by the modulator, which provides ultra-large bandwidth, ultra-high efficiency, and a compact solution for next-generation electro-optic systems.
Publishing source: Laser & Photonics Reviews
