Superefficient microcombs at the wafer level

Chip-scale frequency combs offer massive wavelength parallelization, holding a transformative potential in photonic system integration with potential application in future navigation systems, data center interconnects, and ranging. However, efficient frequency comb solutions have only been reported at the die level. Here, we report the wafer level characterization or soliton microcombs with an average conversion efficiency exceeding 50%, featuring 100 lines at 100 GHz repetition rate with 20 MHz standard deviation. We further illustrate the enabling possibilities of the space multiplicity, i.e., the large wafer-level redundancy, for establishing new sensing applications, and show tri-comb interferometry for broadband phase-sensitive spectroscopy.