High-speed and high-efficiency silicon slow-light modulator based on 1D band-edge waveguides.

Driven by the increasing demand for high-speed and energy-efficient optical interconnects, silicon modulators have emerged as key building blocks due to their compact footprint and CMOS compatibility. Here, we demonstrate a high-speed and high-efficiency silicon MZM based on one-dimensional super-Gaussian apodized slow-light grating waveguides. By operating in a moderate slow-light regime, the device enhances light-matter interaction while preserving bandwidth, achieving a modulation efficiency of 0.34 V·cm within a 124-μm phase shifter. The apodized grating design suppresses mode mismatch and structural reflections, resulting in a low insertion loss of 2.6 dB. A 3-dB electro-optic bandwidth exceeding 70 GHz is obtained, enabling high-speed data transmission up to 144 Gbaud with NRZ signaling. These results indicate that properly engineered slow-light structures can simultaneously achieve high-efficiency and high-speed performance, providing a promising solution for high-density and energy-efficient silicon photonic interconnects.