Modeling and simulation of pipeline security monitoring system based on line-structure sagnac interferometer with 3×3 coupler

作者：He Cunfu^*; Ruan Li; Wu Bin

来源：Transactions of Nanjing University of Aeronautics & Astronautics, 2015, 32(3): 312-317.

DOI：10.16356/j.1005-1120.2015.03.312

• Different frequency
• Distributed optical fiber
• Line structures
• Low-frequency signals
• Model and simulation
• Phase modulation and demodulation
• Sagnac interferometer
• Security monitoring

The third damage action, human disruption behavior, is one of the major threats to pipeline operation. It is necessary to monitor and locate the perturbation behavior that may threat pipeline safety in real-time. Therefore, a new pipeline security monitoring system is designed by using line-structure Sagnac optic fiber interferemeter with the characteristic of 3×3 coupler that can modulate the phase of optic signal, with no need for phase modulation and demodulation. The optic structure of the new system is simplified, the signal processing accuracy is improved, and the polarization effect is reduced. The working principle of the monitoring in ideal condition is described, the phase demodulation is analyzed and the location of the possible damage action point is formulated. By using simulink, the optic signal propagation and interference is simulated and interference signals in different frequencies are obtained. The results validate the feasibility of the monitoring system and indicate that the low frequency signal less than 1 kHz resulting from the human damage action can be detected. The disturbance set at 10 km can be located by calculating the demodulation signal accurately over a long monitoring distance.

• 出版日期2015
• 单位北京大学