| 摘要 |
PURPOSE:To prevent the generation of return light to a semiconductor laser, by leading emitted light from a light emitting element being a light source, into an optical waveguide layer by a grating structure formed on the optical waveguide layer. CONSTITUTION:A light beam emitted from a semiconductor laser 104 goes into an optical waveguide layer 103 by a grating coupler 105, and propagated as a waveguide light 106. The waveguide light 106 is fetched to a space from the optical waveguide layer 103 by a grading coupler 107, and condensed to a recording medium surface 108. A reflected light from the recording medium 108 is led to an optical waveguide layer by a grating coupler 109, propagated, in a mode of waveguide light 110 and detected by a detector 111. A light absorbent 112 is embedded in a part of the optical waveguide layer 103 so that the waveguide light 106 is not superposed on the waveguide light 110. Plural pieces of detectors 111 are placed in a substrate, the waveguide light 110 which is reflected by the recording medium 108 and led to the optical waveguide layer 103 is distributed to each detector, and a reproducing signal and a servo-signal can be obtained. |
