Desensitization elimination in pipeline leakage detection and pre-warning system based on the modeling using Jones Matrix

The principle of the distributed optical fiber pipeline leakage detecting and pre-warning system and the method to eliminate the desensitization are proposed in this paper. To analysis the desensitization which is a common problem of the fiber optic sensor, the optical polarization model of oil and gas pipeline fiber warning system is established in this paper, which is based on the equivalent Jones Matrix of the single-mode optical fiber birefringence. According to the model, the reason of desensitization is polarization fading of two signals, which means that the sensitivity is affected by the polarization direction of the incident light. According to the theoretical model, the solution of using only one external polarization controller to change the polarization direction is put forward. It is proved by the experiment that the solution can solve the problem preferably and improve the locating accuracy and the sensitivity of the system.