| 摘要 |
PURPOSE:To provide a detecting constitution without being affected by the wavelength fluctuation of a laser and returned light from a disk in the photodetector for laser power control of an optical head used for an optical disk device. CONSTITUTION:A laser power is monitored by means of a photodetector 11b receiving the peripheral part of a light transmitted from the front end surface of a laser chip 11a inside a laser diode 11 and is controlled. Since a light quantity incident on a collimator lens and a light quantity received by the photodetector are not affected by the wavelength fluctuation of the laser and the returned light from the disk and always keep a constant ratio, stabilized power control is enabled. |
