Spectrally Uniform Continuous-Variable Quantum Microcombs

Continuous-variable (CV) quantum microcombs generated in high-Q microresonators provide compact, frequency-multiplexed sources of entangled modes for integrated quantum information processing. Although deterministic Kerr-induced two-mode squeezing has been demonstrated on chip, achieving uniform squeezing across a large number of mode pairs remains a central challenge. Here we establish the conditions required for spectrally uniform squeezing and experimentally realize a vacuum-state CV quantum microcomb by combining a microresonator with an engineered single-family mode structure and optimized pump conditions. The device generates 14 independent two-mode squeezed states over a 0.7 THz bandwidth, each exhibiting more than 4 dB of raw squeezing, with a maximum of 4.3 dB. This uniform, high-performance quantum resource represents a key step toward scalable, integrated CV quantum technologies operating beyond classical limits.