Polarization-maintaining fiber is a special type of single-mode fiber. Ordinary single-mode fibers can transmit randomly polarized light, But polarization-maintaining fibers can only transmit polarized light in one direction.

    In polarization-maintaining fibers, the polarization of linearly polarized light waves propagating into the fiber is maintained during propagation with little or no cross-coupling of optical power between polarization planes. This polarization-preserving capability is extremely important for certain fiber optic components that require polarized light input, such as external modulators. By generating stress in the fiber material itself, it can maintain the characteristic that the light wave is polarized in a specific direction. The polarization-maintaining fiber with the following structure is one of the types.

    When the PM fiber is terminated through a fiber optic connector, the stress bar should align with the connector key. Therefore, whether the Key keys are aligned or not, the deviation accuracy of the angle directly determines the function of the PM connector link transmission.