Optical power level-controlling device for stable oscillation of laser diode

An optical power level-controlling device for controlling optical power level of a laser beam emitted from a light-emitting element and irradiated on an optical disk, said optical power level capable of taking an ERASE level defined as a reference level, a BIAS level lower than said ERASE level and a WRITE level higher than said ERASE level, a recording operation on said optical disk being carried out by alternating the optical power level between said BIAS level and said WRITE level, a fixed value control and a feedback control being performed on said ERASE level and on a difference between said ERASE level and said BIAS level, respectively, said device comprising:

• a controlling part in which test signals are recorded while varying the optical power level of the laser beam and in an OPC for setting an optimum WRITE level by reproducing the test signals, said controlling part performing a combined control on said BIAS level during a recording operation of said test signals, said combined control being a combination of a feedback control and a fixed value control at a predetermined ratio, and for performing a fixed value control on said difference between said ERASE level and said BIAS level during a recording operation.