| 摘要 |
The devices switch light from one or more input light guides (30, 36) to selected output light guides (32,38) independetly of the polarization of the light. By applying voltages to liquid crystal film region (40) between parallel sided prisms (31, 37) the perpendicular polarized light component is reflected and the parallel polarized component transmitted. By various means their state of polarization is changed before they are again incident on the film region (41), so that when the perpendicularly polarized component is reflected at this region and the parallel component transmitted, they are both directed into the output guide (38). Correspondingly, in the absence of an electric field, both would be directed into the output guide (32).
<??>The means for changing the polarization includes half-wave plates and quarter-wave plates combined with mirrors at the reflecting surfaces.
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