| 摘要 |
<p>An optical disk device which satisfies a relationship (As cos øs - 1)» - Ds(As2 - 2As cos øs + 1)?2/4μ2¿ or As cos øs = 1 , wherein As denotes the ratio of the amplitude reflectivity of signal marks (27), (28) on the signal surface (16) of optical disk to that of regions outside the signal marks, øs denotes a phase difference, Ds denotes the area of the signal marks (27), (28), and μ denotes a wavelength of a source of light (8). The light reflected by the signal surface (16) is input to waveguide layers (3A), (3B) through grating couplers (4A), (4B) to obtain guided beams (18A), (18B) which are emitted from the ends of the waveguide layers (3A), (3B) and are received by the light detectors (6A), (6B) to obtain control signals and reproduced signals.</p> |
