| 摘要 |
PURPOSE: To suppress a fluctuation in a detection level of a disconnected optical connector even when an output level of an optical amplifier section is changed from a level at initial adjustment. CONSTITUTION: A reflection return light detection circuit 31 detects a reflected return light from an optical transmission line and outputs a voltage corresponding to an optical signal level and a reference voltage generating circuit 30 detects an optical signal outputted from the optical amplifier section 12 and outputs a voltage inverted to a voltage corresponding to the optical signal level as a reference voltage. Furthermore, a comparator 58 is used to compare an output voltage from the reflection return light detection circuit 31 with a reference voltage from a reference voltage generating circuit 31 and provides an output of an optical connector disconnection signal when an output voltage from the reflection return light detection circuit 31 is the reference voltage or over. Then the reference voltage is decreased when the optical signal outputted from the optical amplifier section 12 increases. |
