| 摘要 |
PROBLEM TO BE SOLVED: To compensate the variation of a recording power during recording by making a value, superposing a prescribed power as an offset on the optimum recording power of a light source found in advance, an actual recording power. SOLUTION: At the time of recording, a light output transmitted from a laser diode 21 is converted to a photoelectric current by means of a photodetector 24, converted to a voltage signal by an I/V amplifier 25 and compared with a recording power set value Pwset from an addition part 23 in a compactor part 26. The compared result is compensated in phase by means of a phase compensating circuit 28 and, by feeding it back to a driver 22, feedback control of the light output power of the laser diode 21 is performed so that the difference between the light output power of the laser diode 21 and the recording power set value Pwset is eliminated. The recording power set value Pwset is made by superposing an offset value Pofs on a target value Pw, the variation of the recording power generated during data recording is compensated by feedback control of the set value and the margin of the effective recording power is sufficiently ensured. |
