Optical polarization restoration apparatus

摘要

An active system for restoring the polarization state of light emerging from a single-mode optical fiber. The system changes the slowly varying elliptical polarization resulting from environmental effects on the long fiber to a linear polarization state of fixed orientation. The elliptically polarized light is converted into two orthogonal linearly polarized beams. One of the beams is used in a feedback circuit to null its intensity thereby restoring all the input light to the other linear polarization state.