| 摘要 |
PROBLEM TO BE SOLVED: To provide a recording/reproducing device of not only a high density optical disk but also a low density optical disk by changing a fundamental wave and a harmonic wave to each other by using a SHG blue light source composed of a optical waveguide type wavelength converting element and a variable wavelength semiconductor laser. SOLUTION: A fundamental wave and a harmonic wave on the same optical axis obtained from a SHG blue light source composed of a semiconductor laser and a wavelength converting element is introduced to an optical disk. At this time, the wavelength of a variable wavelength semiconductor laser is changed and the higher harmonic wave and the fundamental wave are selected. At the time of recording/reproducing a high density disk, the higher harmonic wave is used and at the time of recording/reproducing a low density disk, the fundamental wave is used. |
