| 摘要 |
PURPOSE: To form a recording mark of a desired length at a desired position at the time of making an irradiating light a pulse train and switching the power level of a light by temporarily passing the light through a reproducing power level. CONSTITUTION: A laser power is pulse-modulated between a peak level p1 and a bias level p2 with a frequency f1 corresponding to the signals to be recorded. Further, the modulated laser is superimposed with a frequency f2 which is independent of the information signals and is sufficiently higher than the frequency f1 . Thus, the laser power is pulse-modulated between the level p1 or the level p2 and a reproducing light beam level p0 . The time width of the pulse train generated by the frequency f2 is maximized immediately after the change in the laser power corresponding to the frequency f1 , successively reduced and converged to a certain value. When the power is switched from the power p1 to the power p2 or vice versa, the power level passes through the power p0 once. By letting the power level pass through the level p0 once, the effect of a bias light beam is suppressed to a minimum. |
