| 摘要 |
PURPOSE:To prevent the fluctuation of the intensity of light and to improve the speed for recording and reproducing data by providing an optical head equipped with a semiconductor laser wavelength servo circuit composed of a specified equipment and an automatic laser power controller ALPC to modulate laser intensity and pulse width with an acoustic optical element. CONSTITUTION:A semiconductor laser 1 radiates the light in front a/back of a chip. Isolators 2 and 11 prevent the light from returning to the main body of the laser by external reflection and a temperature controller 7 suppress the fluctuation of a temperature to 0.001 deg.. By using a beam splitter 3, the fluctuation of the intensity for the directly reflected light and the reflected light of a Fabry-Perot resonator 4 are measured by an optical detector 5 and defined as an error signal and the injecting current of the laser is fed back. On the other hand, the light is divided into the light to be used for recording, reproducing and erasing the data and light to be used for monitoring the ALPC by a beam splitter 14. Then, the quantity of light for the latter type of the light is detected by an optical detector 15 and fed back to a modulator 10 for which the acoustic optical element is used. |
