MEASUREMENTS OF STRAIN, STRESS AND TEMPERATURE BY USING 1-DIMENSIONAL AND 2-DIMENSIONAL DISTRIBUTED FIBER-OPTIC SENSORS BASED ON SENSING BY POLARIZATION MAINTAINING FIBER OF DISTRIBUTED POLARIZATION CROSSTALK DISTRIBUTION

摘要

Techniques and devices for measuring stress, strain, or temperature based on polarization crosstalk analysis in birefringence optical birefringent media including polarization maintaining fiber. The disclosed techniques and devices can be implemented to measure polarization crosstalk distribution in polarization maintaining fiber by placing the PM fiber in a 1-dimensional or 2-dimensional configuration for sensing temperature, stress or strain in the PM fiber at different locations along the fiber with a high spatial sensing resolution. In some implementations, the disclosed techniques and devices can be implemented to simultaneously measure stress, strain and temperature from analyzing the probe light. For example, both temperature and stress/strain can be simultaneously measured by using the same sensors to extract and separate temperature measurements from stress/strain measurements.

主权项

1. A method for monitoring a temperature of an object by optical sensing, comprising:
coupling a linearly polarized light of a broadband spectrum into an optical birefringent medium as a sensing element which is attached to an object to produce an optical output signal out of the optical birefringent medium; directing the optical output signal to transmit through a linear optical polarizer which is polarized in a direction to cause a mixing between the two orthogonal polarization modes in optical transmission light of the linear optical polarizer; directing the optical transmission light of the linear optical polarizer into an optical interferometer to obtain optical interference of light between the two orthogonal polarization modes in the optical birefringent medium to produce polarization crosstalk peaks; and measuring spacings of polarization crosstalk peaks present in the obtained optical interference to monitor a temperature at different locations of the optical birefringent medium attached to the object.