| 摘要 |
PURPOSE:To maintain light focusing performance by forming a distributed index lens having the optical axis in the direction crossing a substrate and forming grating structure to couple the guided wave propagating in an optical waveguide and the luminous flux passing the distributed index lens to the optical waveguide. CONSTITUTION:The distributed index lens 7a is formed to the other surface side, corresponding to the grating structure 6, of the substrate 2. The distributed index lens 7a is formed by forming a prescribed mask on the surface of the glass substrate 2, subjecting the substrate to a heat treatment in a fused salt of AgNO3, TlNO3, etc., to effect the ion exchange of the univalent ions such as Na ions in the substrate 2 and the univalent ions such as Ag ions and Tl ions in the fused salt. As a result, the lens having the desired good refractive index distribution and good performance is obtd. The slab guided light is then projected continuously at different angles to the grating structure 6 to change the spot positions of the light focused through the distributed index lens 7 in the substrate 2 continuously. A tracking function is thereby realized. |
