Abstract: A reflecting-type optical switch is constructed by stacking a parallel plate-shaped glass substrate and a parallel plate-shaped polarization controller, providing a reflecting portion in such a manner that incident light propagates in zigzag fashion owing to reflection, and depositing a polarizing separating film on the glass substrate where two prescribed incident light beams intersect owing to reflection. Further, a transmission-type optical switch is constructed by providing a polarization controller in front of a polarizing prism, and depositing a polarizing separating film on the glass substrate of the polarizing prism where two prescribed incident light beams intersect owing to reflection. Furthermore, an optical distributor is constructed by stacking a plurality of parallel plate-shaped glass substrates and depositing a partial reflecting film on the glass substrate where two prescribed incident light beams intersect owing to reflection.

Abstract: An optical space switch includes a polarization controller, a beam splitter, a first reflection block and a second reflection block. The polarization controller has a first mode and a second mode. The polarization controller maintains the polarization of input light in the first mode and changes it by 90.degree. in the second mode. The first reflection block includes a quarter wave plate and a light path changing element. The input light from the polarization beam splitter is reflected by the first reflection block. During this time, the input light passes through the quarter wave plate twice. Thus, the polarization of the input light is changed by 90.degree.. Further, the light path of the input light is shifted by a predetermined distance by the light path changing element. The second reflection block has a quarter wave plate and a mirror. The second reflection block receives the input light from the polarization beam splitter, and returns it thereto.