Photonic Quantum Devices And Their Applications

The generation, manipulation, and measurement of photonic quantum states are key functions of all the photonic quantum information systems. Developing novel photonic quantum devices to achieve on-chip integration of these functions is crucial for the practical application of photonic quantum information technologies. We develop photonic quantum devices compatible with contemporary optical networks based on technologies of photonic chips and fiber optics. Through innovations in devices and on-chip systems, we promote the development of photonic quantum information applications such as quantum communication, quantum information processing, quantum sensing and quantum networks.

Representative achievements

- Based on silicon photonic chips and fiber optics, we developed four-wave mixing quantum light sources, enabling the generation of various complex quantum states such as polarization entanglement, frequency entanglement, energy-time entanglement, and hyper-entanglement. These works formed a complete solution for quantum light sources in the telecom band and some of them are developed to commercial equipment.

- Based on silicon photonic chips and thin-film lithium niobate chips, we developed core technologies for on-chip integration of functions such as photonic quantum state generation, manipulation, and measurement, and achieved the polarization-entangled Bell state generation and manipulation chip, the reconstructive photon-counting spectrometer chip, the time-bin encoding to path encoding conversion chip, and so on.

- We applied photonic quantum chip technology to researches of large-scale quantum networks. We proposed a large-scale fully connected quantum key distribution network scheme combining wavelength-division multiplexing and space-division multiplexing, and realized a 40-user fully connected network without trusted-node assistance, with 780 QKD links. We proposed and demonstrated a reconfigurable quantum network scheme based on pump management of four-wave mixing quantum light sources, and achieved deployment on a field optical fiber network testbed. We developed time-bin-encoded quantum teleportation silicon photonic quantum chips and realized a chip-to-chip quantum teleportation experiment over 12.3 km of fiber.

- We achieved innovative results in photonic quantum sensing. Using single-photon detection, we overcame the physical bottleneck of conventional optical time-domain reflectometry (OTDR), which struggles to simultaneously achieve long detection range and high spatial resolution, and realized a photon-counting OTDR system with a spatial resolution of 10 cm over a range of 100 km. Using photon-counting spectrometer chips, we realized a 4D spatial imaging system recovering 3D spatial and 1D spectral information.

Current research focuses

- Photonic quantum chips and on-chip photonic quantum systems

- Key technologies and applications of large-scale quantum networks

- Photonic quantum sensing technology and its on-chip integration

- Novel photonic quantum devices based on new materials and new structures at the micro/nanoscale