Compact slow-light waveguide and modulator on thin-film lithium niobate platform

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 thin-film lithium (TFLN) platform, an ultra-compact SL-MZM length L of ∼370 μm is also constructed. The fabricated SL waveguides show large passband width ∼8 nm, insertion loss 2.9 dB, maximal group index 7.50, corresponding to 3.4 times as that regular TFLN rib waveguide. exhibits EO bandwidth >50 GHz in operating wavelength band nm well. High-speed OOK transmissions at data rates 64 Gbit/s 80 successfully achieved. To our best knowledge, it first time build SL-MZMs bandwidths monolithic platform.