| 摘要 |
PURPOSE:To reduce the connection loss of an optical fiber and an optical waveguide without using extra optical parts by coupling a three-dimensional waveguide directly with a single-mode optical fiber that the core of the tip part deforms in sectional shape smoothly to an ellipse toward the tip. CONSTITUTION:The electromagnetic field distribution 8 of waveguide light 6 traveling in a core varies with the diameter of the core 24. The part of the optical fiber 22 is in single mode, so only light in minimum-degree mode propagates and the main component of an electromagnetic field in two orthogonal axial directions crossing an optical axis at right angles, e.g. lateral electric field has a single peak distribution. The diameter of the core 24 in an end surface 25 is so determined that the electromagnetic field distribution 27 of waveguide light 26 in the end surface 25 of the optical fiber 23 matches with the depth-directional electromagnetic field distribution 14 of the waveguide light of the optical waveguide 3 best. Therefore, the waveguide light 6 in the optical fiber is converted into the waveguide light 26 without any loss and the optical waveguide 3 is excited in the optical fiber end surface 25 with minimum loss to obtain waveguide light 10. Consequently, the coupling loss of the single-mode optical fiber and dielectric three-dimensional optical waveguide is reduced easily. |
