| 摘要 |
PURPOSE:To make it possible to realize the luminous intensity and ON-OFF control of a laser diode at low cost in a simple circuit structure by a method wherein the input signal of the driver of the laser diode is held using a sampling hold circuit and the laser diode is subjected to ON-OFF control while the peak value of the luminous intensity is kept constant. CONSTITUTION:A laser diode LD and a photodiode PD for monitoring the luminous intensity of the diode LD are optically coupled to each other and the output of the diode PD is fed back analogically to a driver 16 of the diode LD to control the luminous intensity of the diode LD. Moreover, the input signal of the driver 16 is held using a sampling hold circuit 19 and the diode LD is subjected to ON-OFF control while the peak value of its luminous intensity is held constantly. Thereby, the luminous intensity of the diode LD and the ON-OFF control of the diode LD in a high frequency can be realized at low cost in a comparatively simple circuit. |
