Low-crosstalk 2*3 optical switch composed of twisted nematic liquid crystal cells

A low-crosstalk structure for a 2*2 optical switch using twisted nematic liquid crystal (TN-LC) cells is proposed. Low crosstalk can be obtained by alternately arranging three TN-LC cells and two walkoff polarizing beam splitters. A 2*2 optical switch is assembled with single-mode fibers. Its insertion loss and crosstalk, in both switching modes, are >