| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical amplifier for a wavelength multiplex optical signal that carries out proper level control respectively to input level variations at a change in the number of wavelengths and at changes in a transmission path loss. <P>SOLUTION: An input optical power variation detection section 18 detects a level changing speed of an input optical signal, and when the detected speed is greater, a control section 21 judges that the input level change results from input power variations at a change in the number of wavelengths and controls the attenuation of an optical variable attenuator 5 to be constant. Conversely, when the detected speed is smaller, the control section 21 judges that the input level change results from input power variations at a change in the transmission path loss and controls the attenuation of the optical variable attenuator 5 so that the optical power per channel at an output port 2 is constant. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
