Research On Stable Phase Technology Of Long-distance Fiber Transmission

Long-distance optical fiber phase-stable transmission technology is a technology that guarantees the phase of the transmitted signal by stabilizing the phase of the long-distance optical fiber link.It has been used in communications,electronic countermeasures,satellites,aerospace,and astronomical observations.Plays a very important role.However,the signal received at the far end will contain phase jitter due to changes in external environmental elements,affecting the accuracy of the signal.Optical fiber has excellent characteristics such as wide bandwidth,low loss,low cost,and little influence by electromagnetic interference.However,long-distance fiber also adds phase jitter to the system.Therefore,real-time and fast compensation of the phase delay generated by the fiber is particularly important.In this way,the phase of the recovered signal at the far end can be kept stable.This paper first discusses the application background of fiber-optic phase-stable transmission systems and the research progress of long-distance fiber-phase-stable transmission technologies at home and abroad.The main application backgrounds are described,including electronic countermeasures and satellite space orbit determination,aerospace,astronomical observations,and transmission distances.Divide the research progress of long-distance fiber phase-stable transmission technology at home and abroad.Starting from the long-distance optical fiber transmission noise mechanism,the influence of each component of the optical fiber transmission link on the noise and the signal stability characterization method are introduced.It can be obtained from the noise analysis of each component.The temperature varies within the range of-10?~25?.The total delay of a 100 km long-distance optical fiber system is about 102 ns,the largest of which is the effect of temperature on the optical fiber delay,which accounts for 99.98% of the total delay.Introduced the long-distance optical fiber phase-stable transmission method,including the principle of phase compensation,and the two-way signal transmission method and phase active and passive compensation methods.Finally,the link compensation technology was compared and analyzed;the principle of traditional jitter measurement methods was discussed.Including harmonic spectrum analysis method,sampling oscilloscope method,phase noise method,optical cross-correlation method and time-domain demodulation method.The principle and process of pulse jitter measurement method using simple coherent sampling method and equally spaced sampling method are studied,and simulation verification is performed with Matlab.The jitter value when the second pulse is not transmitted through the fiber is tested,and the equally spaced sampling method is used.The measurement result is about 13 ps,and the simple coherence method is about 109.02 ps.The jitter error measured by the equally spaced sampling method is smaller and closer to the delay prediction value of the FPGA system.Based on the active compensation method for phase noise,the design the 100 km long-distance optical fiber phase-stable transmission system is verified by simulation.It can quickly correct the peak-to-peak delay of the strong delay in the link up to 30 ns,and reduce the peak-to-peak delay of the system to 90 ps.