  A soliton microcomb can play a crucial role in narrow-grid optical
communications by replacing many independently operated lasers in
wavelength-division multiplexing systems. In this work, we designed and
demonstrated power-efficient soliton microcombs with 100-GHz free spectral
range in an integrated 4H-SiC platform for the first time. The combination of
enabling technologies, including efficient fiber coupling (3 dB insertion
loss), high-quality-factor microrings (intrinsic quality factors up to 5.7
million), and the employment of the Raman effect for adiabatic accessing of the
soliton state, has enabled the demonstration of soliton pump power as low as 6
mW while supporting comb powers above -20 dBm per line near the pump
wavelength.
