Compact slow‐light waveguide and modulator on thin‐film lithium niobate platform
Gengxin Chen, Haohua Wang, Bin Chen, Ziliang Ruan, Changjian Guo, Kaixuan Chen, Liu Liu
Abstract
Abstract Lithium niobate Mach–Zehnder modulators (MZMs) with compact footprint and fast electro‐optics (EO) responses are highly demanded for the next‐generation optical interconnect systems. Here, we demonstrate slow‐light (SL) effect using a coupled Bragg resonator structure on the thin‐film lithium niobate (TFLN) platform, and an ultra‐compact SL‐MZM with length L of ∼370 μm is also constructed. The fabricated SL waveguides show a large optical passband width of ∼8 nm, an insertion loss of 2.9 dB, and a maximal optical group index of 7.50, corresponding to 3.4 times as large as that of regular TFLN rib waveguide. The fabricated SL‐MZM exhibits a large EO bandwidth of >50 GHz in an operating wavelength band of ∼8 nm as well. High‐speed OOK transmissions at data rates of 64 Gbit/s and 80 Gbit/s are successfully achieved. To our best knowledge, it is first time to build SL waveguides and compact SL‐MZMs with large EO bandwidths of >50 GHz on the monolithic TFLN platform.