Glass-based integrated quantum photonic chips： from 2D to 3D

Glass-based integrated quantum photonic chips have been applied to various fields in optical quantum information processing, such as quantum computation, quantum simulation, quantum communication, and quantum metrology, exhibiting powerful functions. This review summarizes the important development of glass-based integrated quantum photonic chips fabricated by three-dimensional high-precision direct writing with a femtosecond laser, especially in quantum computation and quantum simulation. Quantum computing chips include the single-qubit to multiqubit photonic quantum logic gates for universal quantum computation, as well as chips for solving specific problems such as boson sampling, quantum fast Fourier transform, quantum fast hitting, and so on. As for quantum simulation, glass-based quantum photonic chips have become an excellent research platform both for the quantum walk of correlated particles and topological quantum photonics, revealing the evolution of discrete-time and continuous-time quantum walks in one, two and synthetic dimensions, and exhibiting the protection of quantum state transport by robust topological modes in photonic topological insulators.