Optical fiber polarizer based on highly birefringent single-mode fiber

An in-line fiber polarizer is proposed and demonstrated. The attenuation of a single-mode fiber experiencing an axial periodic perturbation shows peaks at certain wavelengths, resulting from the power coupling between the guided mode and the cladding modes. When the fiber has significant linear birefringence, each of these peaks is split into two peaks. The fiber thus exhibits polarization-selective attenuation characteristics. An example of such a polarizer is demonstrated based on a highly birefringent fiber with a beat length of 1.3 mm. A 25-dB polarization extinction ratio is obtained, with an attenuation of 1.3 dB at an operating wavelength of 1177 nm.