THIN FILM WAVEGUIDE TYPE POLARIZING FILTER

PURPOSE:To easily manufacture a polarizing filter and to filter light in TM mode and light in the high-order mode and propagate the light in the TE mode and light in the basic mode by providing a waveguide layer, an intermediate layer which comes into contact with one surface of the waveguide layer and is formed of a material having a lower refractive index than the waveguide layer, and a substrate which comes into contact with the other surface of the intermediate layer and is formed of a material having a higher refractive index than the waveguide layer. CONSTITUTION:This filter is provided with the waveguide layer 13, the intermediate layer 12 which comes into contact with one surface of the waveguide layer 13 and is formed of the material having the low refractive index than the waveguide 13, and the substrate 11 which comes into contact with the other surface of the intermediate layer 12 and is formed of the material having the lower refractive index than the waveguide 13. Guided light which leaks out of the waveguide layer 13 and reaches the substrate 11 is emitted as emission-mode light 16 into the substrate 11 having the higher refractive index, so the guided light is therefore attenuated correspondingly. Therefore, the TM-mode light 15 is attenuated larger than the TE-mode light 14 and this filter functions as a TE transmission and TM absorption type polarizing filter. Similarly, the high-order mode light is attenuated more than the guided light and this filter, therefore, functions as a polarizing filter to the high-order mode light.