Elliptical polarization maintaining fiber extinction ratio measuring device and method

The invention discloses an elliptical polarization maintaining fiber extinction ratio measuring device and method. The device includes a wide-spectrum light source, a polarizer, a polarization controller, a fiber to be measured, a polarization analyzer, a fiber adapter and a computer that are sequentially connected. The wide-spectrum light source forms linearly polarized light with a high extinction ratio through the polarizer, the polarization analyzer is combined with the polarization analyzer, so that the polarization state input to the fiber to be measured is consistent with the polarization intrinsic state of the fiber, and then the stokes parameter changes of the Poincare sphere are recorded, the variance of the power of the polarization intrinsic state and the power of another polarization intrinsic state orthogonal to the polarization intrinsic state, and the extinction ratio of the fiber to be measured at the length is obtained; the decibel difference of the two extinction ratios before and after the