| 摘要 |
PURPOSE:To stabilize an optical output and to improve reliability by a method wherein the driving current of a semiconductor laser is controlled by means of monitoring a part of the photo output signals emitted from one end of a laser. CONSTITUTION:The photo output emitted from a semiconductor laser 1 is spectroscopically analyzed by means of a spectroscope such as a prism or halfmirror etc. A part of the photo output thus analyzed is converted into current by means of a photo-current conversion circuit 3 comprising photo-current conversion element such as photodiode, phototransistor etc. The converted current is compared with the reference current from a reference current generating circuit 4 with a reference current generator generating the reference current corresponding to the specified photo output in a current comparison circuit 5 comprising operation amplifier etc. The output current from the current comparison circuit 5 is inputted into a semiconductor laser driving circuit 7 comprising a constant current voltage supply source through the intermediary of a semiconductor laser current control circuit 6 to control the driving current of the semiconductor laser 1. |
