| 摘要 |
PROBLEM TO BE SOLVED: To realize prevention of occurrence of a signal error in other wavelength bands due to a fixed gain or attenuation of an optical amplifier in the case that part of wavelength bands is interrupted or fluctuated regardless of a simple circuit configuration. SOLUTION: This controller is provided with a pair of optical detection means 36a, 38a and 36b, 38b with different wavelength characteristics in quantum efficiency to detect multi-wavelength optical amplifier output, part wavelength fluctuation detection means 42a, 42b, 44 that detect interruption or fluctuation on only part of wavelength bands on the basis of the detected level and a stop means 46 that stops automatic level constant ALC control in the case that the interruption or fluctuation in only part wavelength bands is detected. Thus, the purpose above can be realized with a simple circuit configuration without the need for a spectrum analyzer and it is not required to slow down a response speed of the ALC control. |
