High-performance dual-band silicon slow-light modulator for DWDM chip-scale applications

This paper presents a silicon slow-light modulator based on cascaded phase-shifted Bragg grating (PSBG) structures, which supports C/L dual-band modulation and demonstrates consistent wavelength channel performance across these bands. The modulator has an ultra-compact modulation length of only 201 µm, a normalized insertion loss of 5.3 dB, an electro-optic bandwidth of up to 85 GHz, and an OOK modulation speed of up to 128 Gbaud. Notably, it features a breakthrough in operational bandwidth, with a flat passband exceeding 20 nm in both C and L bands, and achieves an energy efficiency of 0.242 pJ/bit. The design integrates CMOS compatibility, small footprint, low insertion loss, high bandwidth, and extensive working wavelength range, providing an efficient solution for high-density wavelength division multiplexing (DWDM) chip-scale interconnects.