| 摘要 |
PURPOSE:To eliminate the generation of instantaneous break off of optical output during changeover time and prevent rush current. CONSTITUTION:When the control signal voltage V of a drive current change over control circuit shown voltage V1 which is smaller than a reference voltage, a first transistor 3 conducts while a second transistor 4 is cut off so that the current I of a piezoelectric current source may flow to a first excitation laser 1. When the control signal voltage V shows voltage V2 larger than the reference voltage, the second transistor 4 conducts while the first transistor 3 is cut off, thereby allowing the current of the piezoelectric current source 5 to flow to an excitation layer 2. The first transistor 3 and the second transistor 2 conductor so that the current flows to both the first excitation laser 1 and the second excitation laser 2. However, the total sum of the current is held at the current 1 of the piezoelectric current source 5. |
