A Heterogeneous Silicon on Lithium Niobate Modulator for Ultra-Compact and High-Performance Photonic Integrated Circuits

We propose a heterogeneous silicon on lithium niobate (Si-LN) modulator which improves the compactness and modulating performance of large-scale photonic integrated circuits. Two types of configurations are employed on the Si-LN wafer for ultra-compact light-routing waveguides and high-performance light-modulating waveguides, respectively. The low loss taper transfers the optical modes between the two waveguides. In the heterogeneous Si-LN modulator, LN etching is nonessential and thus device processes are supported on a robust wafer. Our design analyzes the influence of the LN thickness on the performance. According to theoretical analysis and numerical simulation, the modulator supports a bend radius of 10 μm and edge-to-edge waveguide separation of 0.7 μm with respect to ∼1 cm beat length. When thickness of LN is 700 nm, the modulation efficiency reaches 1.76 V⋅cm and the bandwidth exceeds 350 GHz. This modulator is potentially suitable for ultra-compact, large-scale, high efficiency, and large bandwidth photonic integrated circuits (PICs).