| 摘要 |
PURPOSE:To simplify the adjustment and to prevent the occurrence of an effect of an erasing beam at the time of recording by splitting a light beam from one light source into two light beams having different polarization directions, making one beam incident upon a Faraday element and performing an optical modulation with an impressed voltage. CONSTITUTION:The light beam 2 emitted from a laser diode 1 is splitted by a beam splitter 4 into an S-polarization component is transmitted to become the erasing beam 5. On the other hand, the S-polarization component is reflected and passed through the Faraday element 6, and then after reflection, it is passed again through the Faraday element 6 and the beam splitter 4, so that only the P-polarization component is incident upon a 1/4 wavelength plate 8 having a reflecting film. This reflected light 9 is turned into the light consisting of its S-polarization component only again, and is reflected by the beam splitter 4 to become a recording and reproducing beam (collimator light) 10. At the time of recording, the recording beam 10 is modulated by changing a voltage to be impressed upon the Faraday element 6, and at the time of reproducing, a signal is read out by lowering an output of the laser diode 1 below its recording level. |
