Research on fiber optic phase-stable transmission technology based on optical true-time-delay

In order to meet the microwave signal transmission requirements of distributed coherent radar antenna, a broadband optical fiber phase stabilized transmission system based on optical true-time-delay was designed. The system consisted of optical true-time-delay measurement, optical delay compensation, and optical fiber transmission of microwave signal based on wavelength division multiplexing. The multi frequency signal phase ranging technology was adopted. And the technical scheme of variable optical delay line combining high-precision mechanical delay and bit delay was adopted, which had sub picosecond measurement and compensation accuracy. An 8-channel experimental system was built, and the feasibility of the system scheme was verified in the optical fiber transmission system with a length of about 2 km. The results show that, the stability accuracy of true-time-delay in channels is better than 1 ps, and the consistency of delay between channels is better than 1.7 ps. This study provides a reference scheme for transmission of step-by-step broadband radio frequency signals.