Time is one of the seven basic physical quantities. It is also the most accurate one. With current technology, the accuracy of the optical clock can be maintained in the order of magnitude 10-18. However, the current remote transmission technologies in China are unable to meet the requirement of calibration between high precision optical clock. The fiber-based time-frequency transmission can reach the level of 10-19 on the distance larger than 1000 km. It becomes the most hopeful scheme of future ground clock network.
Our project focuses on the time-frequency transmission with current existing quantum key distribution fiber network. We shall develop ultra-narrow band laser, high speed opto-electronic feedback technology, and high precision timing synchronization technology. Based on this, we shall implement frequency calibration between two remote optical clock, quantum metrology and detection of dark matters. Moreover, the developed technology can find applications in many quantum information tasks including measurement device independent quantum key distribution and quantum finger printing and quantum repeater.
- Towards satellite-based quantum-secure time transfer. Nature Physics (2020).