Calibration of lasers that produce multiple power output levels of emitted radiation

摘要

A laser calibration apparatus and method first calibrates a maximum laser power level. Then lesser laser power levels are calibrated. A separate calibration pattern is used for calibrating each of the laser power levels. The calibration patterns used for the lesser laser power levels include the calibrated maximum laser power level. Such inclusion established a fixed relationship between the maximum laser power level and all of the lesser laser power levels. The calibration is performed on an optical disk, preferably of the magneto optical type. The calibrated laser power levels are then used to record pulse-width modulated signals.