| 摘要 |
PURPOSE:To obtain a waveguide type optical attenuator which attenuates and annihilates TE mode and can output only the TM mode as output light by forming an optical waveguide projecting on a substrate and forming a metallic film on the side face of the optical waveguide. CONSTITUTION:An optical waveguide 12 is projected and formed on a substrate 1. A metallic film 13 is formed on one side face of the waveguide 12 and a part on the substrate 11. The refractive index of the waveguide 12 is higher than that of the substrate 11 and higher than the refractive index of air. The light made incident on the waveguide 12 from one end thereof propagates therefore in the direction Z in the waveguide 12. The light of the TE mode out of the propagating light is lost and successively annihilated by the metallic film 13 formed on the side face of the waveguide 12. Only the light of the TM mode is therefore taken out of the other end of the waveguide 12. |
