| 摘要 |
PROBLEM TO BE SOLVED: To realize high quality wavelength multiplex transmission by providing an optical transmitter with a wavelength setting means which sets the wavelength of insertion signal light so that the difference between the wavelength of the insertion signal light and the wavelength of inputted signal light becomes equal to the wavelength difference defined in advance. SOLUTION: In separation signal light separated by optical cross connects 7, a part of signal light is separated by an optical directional coupler 10 so that its wavelength can be monitored to be inputted to a wavelength comparing part 12. Meanwhile, in insertion signal light outputted from an optical transmitter 9, a part of outputted insertion signal light is branched by an optical directional coupler 8 to be inputted to the part 12. The part 12 monitors respective wavelengths of separation signal light and insertion signal light in a light add/drop multiplexer(ADM), detects the wavelength difference between them and transmits wavelength difference information to the transmitter 9 so as to maintain the wavelength difference on a fixed level. The transmitter 9 controls the wavelength of the insertion signal light and performs feedback control of the wavelength the insertion signal light so that wavelength difference that is preliminarily defined with the wavelength of the separation signal light may be maintained. |
