| 摘要 |
PURPOSE:To perform the magneto-optical recording and reproducing by arranging the transparent substrate placing a pair of grid couplers whose grids are crossed at a specific angle between the lenses located between a laser light source and magneto-optical disk, a pair of nonreciprocal discoid double refraction plates, a diffracted light waveguide and an optical detector. CONSTITUTION:The light of a laser 22 is passed through a lens 23, receiving the rotary polarization via a pair of transparent substrates 29, 33, waveguides 30, 34, diffraction grid couplers 24, 26 and nonreciprocal discoid double refraction plates 25, 27 and projected on a magneto-optical disk 21. In this case, the magnetizing direction of the magnetic body of the disk is selected by an electromagnet 20 in the case of a writing and erasing. At the time of reproducing the reflection light of the disk varies at + or - theta for the magnetizing direction. The polarized plane is rotated by a refraction plate 27 and the diffracted light is combined with a waveguide path 34 by the grid coupler 26. The transmitting light of the coupler 26 is also combined with the waveguide path 30 by the coupler 24 and taken off by lenses 35, 32. Then reproducing is performed by using the output of detectors 36, 32 by keeping S=e-(a+b+c+ d)=0, by focusing with F=(a+d)-(b+c)=0 and the tracking is performed by T=(a+b)-(c+d)=0. |
