256-Gbps Whispering-Gallery Mode Enhanced Silicon Microring Modulator with a Free Spectral Range of 4.5 THz

We demonstrated a silicon microring modulator with an uncorrupted free spectral range of 4.5 THz. A single-lane data rate of 256 Gbps utilizing PAM-4 can be achieved, highlighting its potential for advancing high-bandwidth wavelength-division multiplexing communications.