| 摘要 |
PURPOSE:To enable pulse current flow through a semiconductor laser diode to be regulated continuously, and to enable optical output power to be varied continuously, by connecting a constant voltage circuit consisting of a second FET to the source electrode of a first FET. CONSTITUTION:When the gate voltage VG2 of an FET 2 is so controlled as to decrease the drain current ID2, i.e., cut off the FET 2, the current flow through the source resistor 4 of a FET 1 is also decreased so that the source voltage VS1 of the FET 1 is reduced. As a result, the voltage VD1S1 across the drain and source of the FET 1 is increased to enhance the amplitude of pulse current. In such a manner, the gate voltage of the FET 2 forming a constant voltage circuit is so controlled that the voltage across the drain and source of the FET 1 can be changed to vary the driving pulse current continuously. Therefore, the optical output power of a semiconductor laser can be also varied continuously. |
