| 摘要 |
PURPOSE:To improve the outgoing efficiency and to reduce the size by providing a reflecting means which reflects waveguide light, passed through a grating for light outgoing without outgoing, so that the light is in phase with outgoing light. CONSTITUTION:The grating 12 for light outgoing is formed at a specific place on the optical waveguide 11. Assuming that incident light is entered into the optical waveguide layer 11 from the left side, a reflection type grating 13 is formed on the right side of the grating 12 for light outgoing at a specific distance (d). In this case, the reflection type grating 13 reflects and returns the light, which passes below the grating 12 without outgoing from the grating 12 for light outgoing to travel to the right, to the grating 12, and the light is outgone from the grating 12 in the in-phase relation with the light outgone from the grating 12 for light projection. Consequently, the outgoing light power is increased and the high projection efficiency is obtained. Further, the grating for light outgoing need not be so long, so the side is reducible. |
