  Increasing the number of entangled entities is crucial for achieving
exponential computational speedups and secure quantum networks. Despite recent
progress in generating large-scale entanglement through continuous-variable
(CV) cluster states, translating these technologies to photonic chips has been
hindered by decoherence, limiting the number of entangled entities to 8. Here,
we demonstrate 60-mode CVcluster states in a chip-based optical microresonator
pumped by chromatic lasers. Resonantly-enhanced four-wave mixing processes
establish entanglement between equidistant spectral quantum modes (qumodes),
forming a quantum analogue of optical frequency combs. Decoherence is minimized
to achieve unprecedented two-mode raw squeezing (>3 dB) from a chip. Using
bichromatic and trichromatic pump lasers, we realize one- and two-dimensional
cluster states with up to 60 qumodes. Our work provides a compact and scalable
platform for constructing large-scale entangled quantum resources, which are
appealing for performing computational and communicational tasks with quantum
advantages.
