| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical fiber amplifier which is economical only with monitoring photodiodes of an input stage and an output stage without using a high-cost photodiode in the optical fiber amplifier having a detecting function of disconnection of an output optical connector, and also to provide the method of detecting disconnection of an optical output connector. <P>SOLUTION: The optical fiber amplifier applies a high-speed modulation signal to an amplifying excited LD light source and receives by the optical output monitor of a rear stage. Meanwhile, a return light generated when the output optical connector of the optical fiber amplifier is disconnected, is taken out by a front stage monitor PD, and inputted together with the optical output of the rear stage monitor PD to a differential amplifier. When a voltage obtained by differentially amplifying both the outputs exceeds a predetermined voltage threshold value, the disconnection of the output optical connector is detected, the operation of the excited light source (excited LD) is stopped, and generation of an unnecessary optical radiation to an external output is prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
