| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength-multiplexed light transmitting equipment capable of holding the optical intensity of each wavelength of an amplified optical signal at a fixed level independently of the number of wavelength-multiplexed optical signals. SOLUTION: First and second optical transmission boards 12, 13 output optical signals superposed by sine wave signals with respectively different frequency bands and having mutually different wavelength values. These optical signals are multiplexed by an optical multiplexer 16 and the multiplexed signal is branched to two signals by an optical distributer 18. One branched signal is amplified by an optical fiber amplifier 21. The other is converted into an electric signal by a photodiode 25, the superposed sine wave signal components are extracted from the electric signal by 1st and 2nd band pass filters 28, 29 and the existence of signals to be extracted is detected by output detectors 31, 32. An adder 33 outputs a reference voltage signal 34 with voltage corresponding to the number of detected signals. A gain control circuit 46 controls amplification gain so as to obtain an output light level matched with the number of signals based upon the voltage value corresponding to the light intensity of the output light and the voltage value of the reference voltage signal 34. |
