| 摘要 |
PURPOSE:To obtain a constant optical output power independently of the temperature change even if a laser diode possessed of any kind of a temperature property is used by a method wherein a direct bias current value and a pulse signal current value are both set corresponding to a light emitting condition of the laser diode. CONSTITUTION:A direct bias current ID is so set as to make the value of G1.R.m sufficiently larger than 1. By that, an equation 1 is satisfied. And, output voltages V16 and V17 of amplitude detecting circuits 16 and 17 are as follows: V16=R.(amplitude of iout)=R.m.Ip; V17=R.(amplitude of ia)=R.IA. By those, a relative equation 2 can be obtained. In the equation 2, G2 is a conversion conductance of a voltage/current converting circuit 18, and I02 denotes a balanced output current (output current when two input voltages V16 and V17 are equal to each other) of the voltage/current converting circuit 18. That is, even if a luminous efficiency (proportional to m) changes due to the temperature change of the laser diode 1, an amplitude IP of a pulse signal current ip changes automatically through the function of a feedback loop following the change of the luminous efficiency. |
