JPS6443816A - System for modulating laser power for recording - Google Patents

Abstract

PURPOSE:To cause the rise of a highest temperature distribution curve to be step and large by executing the necessary control of the laser power of the constant section immediately before and after the rise of a recording signal. CONSTITUTION:An output (a) to obtain the timing of data from a circuit part 1 and an output (b) to shift one clock are supplied to a circuit part 4 equipped with delaying elements 5a and 5b, an inverter 6, an AND gate 7, etc. A signal (e) to shift, for several clocks, a recording signal, a constant section detecting signal (h) immediately after a recording signal rise and a constant section detecting signal (g) immediately before the rise are impressed to respective current generating circuits 13-16 from a circuit part 8 having D type FF9-12. The output of these generating devices 13-15, etc., is supplied through an adding point to a laser diode LD, and for the constant section immediately before the rise of the recording signal, the laser power is lowered and for the constant section after the rise, the power is strengthened. Thus, the rise of the highest temperature distribution curve at the time of recording is steep and large, the temperature dependency is minimized and a recording margin is made larger.