A Time-Domain Detection System for Dual Polarization Optical Fiber Vibration Sensing

Abstract

The invention discloses a double-polarization-state optical-fiber vibration sensing time domain detection system. The system performs the following steps: light splitting is performed on a sensing optical signal to generate a first light beam and a second light beam; a current light power value of the first light beam is detected; the second light beam is input into a double-polarization-state polarization analyzer, and then is output to be a first polarization light beam and a second polarization light beam; a polarization light power value of a third polarization light beam and a polarization light power value of the second polarization light beam are detected, and a deviation absolute value set of the polarization light power values of the third and second polarization light beams; a double-polarization-state energy absolute value set is generated; a relative energy value is calculated according to the current light power value of the first light beam and the double-polarization-state energy absolute value set; and whether an optical-fiber vibration exists is determined according to the relative energy value and a preset relative energy threshold. The system can achieve detection of the optical-fiber vibration without adding a polarization controller and using a polarization maintaining optical fiber in a cost-limited optical-fiber polarization state vibration sensing system.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and more specifically relates to a dual polarization state optical fiber vibration sensing time domain detection system. Background technique [0002] In a cost-constrained fiber optic vibration sensing system, only a single analyzer can be used to determine whether vibration has occurred on the sensing fiber line. However, the polarization state of the beam emitted by the light source changes with temperature. This problem may cause fluctuations in the sensitivity of the optical fiber polarization state detection vibration sensing system, and then false positives or false positives of the sensing system may occur. Adding a polarization controller to stabilize the light source may bring a relatively large increase in cost to the cost-constrained polarization state detection vibration sensor system. [0003] On the other hand, in the cost-constrained optical fiber polarization stat...

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Problems solved by technology

[0004] Although the use of polarization-maintaining fiber can partially stabilize the impact of environmental changes or differences in fiber quality, the material cost and deployment cost of polarization-maintaining fiber are too high, and it is difficult to be widely used in cost-constrained fiber-optic polarization detection vibration sensing systems

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