Optical output controller with control based upon an output current of parallel current controlling elements

An optical output controller comprising:

• a light source;
• a light receiving unit detecting light emitted from the light source and converting the detected light into a current signal;
• and
• an automatic power controlling unit receiving current from the light receiving unit and controlling an optical power output of the light source in accordance with the received current, wherein the automatic power controlling unit includes a resistance circuit section having a variable resistor connected to an output end of the light receiving unit, a resistor connected in parallel with the variable resistor, and a load resistor connected in series with the variable resistor and a node providing a predetermined voltage, and a comparison circuit section controlling a driving current of the light source by comparing an output current of the resistance circuit section with a predetermined signal,
• wherein the node of the load resistor for providing a predetermined voltage is connected to a power supply providing a predetermined voltage (VCC), and
• the automatic power controlling unit further comprises a capacitor having one end connected in series with the power supply and the load resistor and the other end being connected to ground.