The three-dimensional waveguide chip is prepared by femtosecond laser direct writing technology, which can realize the processing and preparation of any three-dimensional shape structure, making it possible for on-chip three-dimensional photonic integration. Through femtosecond laser direct writing technology, miniaturized, low-loss three-dimensional waveguide chips with low transmission loss, circular cross-section, and highly symmetrical mode field can be prepared on a glass substrate, which is of great significance for the realization of high-density optical interconnect products. Shenzhen Optics Valley can provide customized three-dimensional waveguide chips according to actual application scenarios and needs.