| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the S/N of an optical main signal by allowing a transmission side to suppress an amplification frequency component of the optical main signal generated inside a repeater. <P>SOLUTION: A wavelength multiplex transmission system is provided with: an optical reception section (a photocoupler 2 and a photoelectric converter 3) for converting the optical main signal into an electric signal; an electric filter section (electric filters 4, 5) for extracting a signal component with the same frequency band as that of a monitor control signal and a signal component with a frequency band at which the communication of the monitor control signal is hindered from the electric signal; an adjustment section (phase shift circuits 6a, 6b, level adjustment units 7a, 7b, and an adder 8) for adjusting the phase of the signal components to be inverted and generating an adjustment signal; and a modulation section (an adder 9, a stimulation semiconductor laser diode 10, a wavelength multiplex coupler 11, and a Raman amplifier 12) for summating the monitor control signal and the adjustment signal to generate a modulation signal, applying optical conversion to the generated modulation signal to generate modulation light, and applying composition and superimposing modulation to the modulation light and the optical main signal to output a modulated optical main signal. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
