WRITE LASER POWER SETTING DEVICE AND METHOD

摘要

A device for setting a write laser power for writing data on a recording medium includes first and second oscillators for producing carrier signals having high frequencies f1 and f2. The carrier signals are added to produce a sum signal that is applied to a driver for producing a laser drive signal. The power of the laser drive signal is changeable among various levels. Using the laser drive signal, a write/read head writes test signals at preselected areas on the recording medium with different writing power levels applied to different preselected area. After writing the test signals, the head reads the recorded test signal. From the read signals, an unwanted signal having a frequency f1-f2 is filtered, and the level of this unwanted signal is detected and stored. A minimum value of the stored levels is selected, and the area at which the minimum value was obtained is detected. The writing laser power is then set at a level corresponding to the level used for writing the test signal in this detected preselected area.