| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve playback accuracy of information recorded on an optical disk. <P>SOLUTION: The optical pickup 7 separates a light beam L1 to a signal light beam Lsig1 and a reference light beam Lref1, and makes the reflection signal light beam Lsig1 reflected on the optical disk 100 incident on a non-polarizing beam splitter 17. An acousto-optic modulator 18 modulates a frequency of the reference light beam Lref1 to generate a modulation reference light beam Lref2. A light path length adjustment section 20 adjusts the reference light path length LPref so that a light path length difference between a signal light path length LPsig and a reference light path length LPref becomes a coherent distance of the light beam L1 or shorter. Further, the optical pickup 7 generates a multiplex light beam Lmul by multiplexing the modulation reference light beam Lref2 and a reflection signal light beam Lsig2 on the non-polarizing light beam splitter 17, and receives it by a detector 21 to generate a light receiving signal. <P>COPYRIGHT: (C)2011,JPO&INPIT |
