| 摘要 |
PURPOSE:To manufacture an automatic laser output control circuit, differential quantum efficiency of which is not increased on the low temperature side, by inputting the output control signal of a first current control circuit to a laser pulse-signal driver circuit as a control signal and the output control signal of a second current control circuit to a laser bias circuit as a control signal. CONSTITUTION:A pulse current value is fixed by a control signal 105 as an output from a first current control circuit 3 so that a laser drive signal 102 as an output from a laser pulse-signal drive section 1 is brought to the constant value of pulse currents at all times under a temperature state requiring bias currents higher than laser-diode threshold currents at a fixed temperature from the temperature characteristics of a laser diode 5, a bias circuit 2 is controlled by a control signal 106 as an output from a second current control circuit 4, and a laser drive signal 103 as laser bias currents is adjusted. A laser output is controlled so that a constantly fixed optical output signal 107 is acquired even when threshold currents are increased by the temperature characteristics of the laser diode 5 and differential quantum efficiency is reduced. |
