Method for normalizing the write laser power of magneto-optical disk drives by using a calibration disk

Normalization of write laser power is important for facilitating the device-independent use of optical disks in optical disk drives produced by different manufacturers. In this paper, we describe methods for normalizing laser power by using a calibration disk, for maintaining the guaranteed characteristics of the calibration disk, and for maintaining the performance of a measurement system used to evaluate the calibration disk. We also give test results relating to the methods for a long period of over 3 years.