▎ 摘　　要

We propose a graphene-based all-fiber optical switchable polarizer, which can operate on either the transverse electric (TE) or transverse magnetic (TM) mode. Graphene layers are placed on the four sides of the microfiber surface. By simply adjusting the applied voltages on graphene in horizontal and perpendicular directions, either a TE-or TM-pass polarizer can be configured in the all-fiber structure and their states can be switched with the change of the direction of applied voltages, which has not been reported previously. The simulation results show that large differential loss per length between two modes can be obtained, which means a large extinction ratio over 17 dB with length of 2.5 mm is achieved for both TE-pass polarizer and TM-pass polarizer. Compared with conventional optical polarizers, the proposed polarizer combines the distinctive advantages of the all-fiber structure and graphene-based devices, outstanding with large extinction ratio, broadband operating waveband and being unaffected by temperature.