| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a light amplifier preventing excessive stress application to a semiconductor laser that constitutes optical repeater circuits by instantly responding to a fluctuation in an abrupt feed current to prevent an overcurrent from being fed to the optical junction circuits. <P>SOLUTION: Since it is constituted so that the response speed of an overcurrent suppression circuit 13 wherein a current detection circuit 16, a current source control circuit 18 and a current source 15 operate as a control system is made faster than the fluctuation speed of a feed current which is made to rapidly fluctuate by a lightning surge or the like, even though an abrupt fluctuation occurs in the feed current, the overcurrent suppression circuit 13 instantly responds to the fluctuation to increase the load of the current source 15, an excessive current is bypassed through a constant voltage diode 14, and the fluctuation in the feed current caused to flow to the current source 15 can be suppressed. As a result, the overcurrent is prevented from being fed to optical junction circuits 11a and 11b to be able to prevent excessive stress from being given to the semiconductor laser constituting the optical junction circuits 11a and 11b. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
