This paper presents the on-chip generation of high-dimensional entangled quantum states and their coherent control. The researchers demonstrate the creation of entangled quDit states, where photons are generated in a coherent superposition of multiple high-purity frequency modes. They achieve a quantum system with at least 100 dimensions, formed by two entangled quDits with D = 10. Using state-of-the-art telecommunications components, they introduce a coherent manipulation platform to control frequency entangled states, capable of performing deterministic high-dimensional gate operations. They validate this platform by measuring Bell inequality violations and performing quantum state tomography. Their work enables the generation and processing of high-dimensional quantum states in a single spatial mode. Integrated photonics is used to fabricate optical waveguides and functional devices on compact and mass-producible chips. This technology allows for the compact, cost-efficient, and stable generation and processing of non-classical optical states. The researchers use a spectrally-filtered mode-locked laser to excite a single resonance in an integrated nonlinear microring resonator, producing pairs of correlated signal and idler photons. These photons are generated in a superposition of multiple frequency modes, leading to the realization of a two-photon high-dimensional frequency-entangled state. The researchers perform two experiments to characterize the dimensionality of the generated state. They measure the joint spectral intensity, describing the two-photon state's frequency distribution. They also evaluate the Schmidt number of their source, which describes the lowest number of significant orthogonal modes in a bipartite system. They find that the number of significant orthogonal modes is indeed 10. The researchers demonstrate the generation of high-dimensional entangled states with up to 10 dimensions. They show that these states can be used for quantum information processing, including quantum computing and quantum communication. They also show that these states can be used for fundamental investigations of quantum nonlocality and high-dimensional quantum state characteristics. The researchers use a frequency-domain approach to generate high-dimensional entangled two-photon states in an integrated platform. They achieve flexible coherent control of these states through the manipulation of their frequency components using state-of-the-art programmable telecommunications filters and off-the-shelf RF-photonics components. This makes possible the simple execution of D-dimensional manipulations and mode-mixing operations in a single, robust spatial mode, further enabling their combination with other entanglement concepts. The researchers also demonstrate that their approach can easily support the generation and control of even higher dimensional states. They show that this can be achieved by decreasing the FSR of the resonator and using a programmable filter with a higher frequency resolution to access the full dimensionality of the generated state. They also show that their results indicate that microcavity-based high-dimensional frequency-entangled states and their spectral-domain manipulation open up new venues for reaching the processing capabilities required for meaningful quantum information science in a powerful and practical platform.This paper presents the on-chip generation of high-dimensional entangled quantum states and their coherent control. The researchers demonstrate the creation of entangled quDit states, where photons are generated in a coherent superposition of multiple high-purity frequency modes. They achieve a quantum system with at least 100 dimensions, formed by two entangled quDits with D = 10. Using state-of-the-art telecommunications components, they introduce a coherent manipulation platform to control frequency entangled states, capable of performing deterministic high-dimensional gate operations. They validate this platform by measuring Bell inequality violations and performing quantum state tomography. Their work enables the generation and processing of high-dimensional quantum states in a single spatial mode. Integrated photonics is used to fabricate optical waveguides and functional devices on compact and mass-producible chips. This technology allows for the compact, cost-efficient, and stable generation and processing of non-classical optical states. The researchers use a spectrally-filtered mode-locked laser to excite a single resonance in an integrated nonlinear microring resonator, producing pairs of correlated signal and idler photons. These photons are generated in a superposition of multiple frequency modes, leading to the realization of a two-photon high-dimensional frequency-entangled state. The researchers perform two experiments to characterize the dimensionality of the generated state. They measure the joint spectral intensity, describing the two-photon state's frequency distribution. They also evaluate the Schmidt number of their source, which describes the lowest number of significant orthogonal modes in a bipartite system. They find that the number of significant orthogonal modes is indeed 10. The researchers demonstrate the generation of high-dimensional entangled states with up to 10 dimensions. They show that these states can be used for quantum information processing, including quantum computing and quantum communication. They also show that these states can be used for fundamental investigations of quantum nonlocality and high-dimensional quantum state characteristics. The researchers use a frequency-domain approach to generate high-dimensional entangled two-photon states in an integrated platform. They achieve flexible coherent control of these states through the manipulation of their frequency components using state-of-the-art programmable telecommunications filters and off-the-shelf RF-photonics components. This makes possible the simple execution of D-dimensional manipulations and mode-mixing operations in a single, robust spatial mode, further enabling their combination with other entanglement concepts. The researchers also demonstrate that their approach can easily support the generation and control of even higher dimensional states. They show that this can be achieved by decreasing the FSR of the resonator and using a programmable filter with a higher frequency resolution to access the full dimensionality of the generated state. They also show that their results indicate that microcavity-based high-dimensional frequency-entangled states and their spectral-domain manipulation open up new venues for reaching the processing capabilities required for meaningful quantum information science in a powerful and practical platform.