The Degree of Polarization-Induced-Fading for Fiber-Optic Sensor Based on 3×3 Coupler

The optical fiber sensors have been paid increasing attention and are widely used and researched in-depth. However, polarization fading phenomena always appear in the output of interferometric fiber-optic sensors. In this paper, we use polarization optics to study polarization-induced fading phenomena and calculate the degree of it in the sensor based on 3 × 3 coupler. The result shows that the minimum of output light intensity is 0. We must change the structure of the sensor or use eliminating polarization-induced-fading technique to get steady laser intensity signals.