Optical switch.

摘要

An optical switch comprises a first polarization converter, and a second polarization converter which is provided in series with the first polarization converter. The first and second converters are able to select as emitted light one of two perpendicular polarized light components of incident light having a desired wavelength ( lambda 0) in a polarized state. The first polarization converter converts the incident light into a polarized light component corresponding to one of two points positioned at opposite sides to each other on a Poincaré sphere and obtained by rotating the incident light at +90 DEG or -90 DEG around an axis perpendicular to an axis passing through a point corresponding to the incident light on the Poincaré sphere and the center of the Poincaré sphere. The second polarization converter converts the polarized light obtained by the first polarization converter into polarized light corresponding to a point obtained by rotating the two polarized light components at +90 DEG or -90 DEG around an axis passing through the above-mentioned two points on the Poincaré sphere.