Semiconductor laser drive device, optical head, optical disk device and optical disk recording and reproducing method

摘要

According to the present invention, a semiconductor laser drive device is provided with a high-frequency superimposing circuit to superimpose a high-frequency current on a laser diode and a superimposed frequency changing circuit to change the superimposed frequency and the amplitude of high-frequency current responsive to an operation mode of an optical disk device, wherein the respective superimposed frequency and the amplitude between at least a first output power and a second output power from the semiconductor laser are changed in response to the operation mode of the optical disk device. This not only enables the high-frequency superimposition of a plurality of frequencies and the mode optimization but also facilitates the reduction of laser noises.