| 摘要 |
PROBLEM TO BE SOLVED: To allow for proper wavelength control of the signal light containing light of a plurality of wavelengths.SOLUTION: Signal light containing light of a plurality of wavelengths, set in a predetermined transmission band, is transmitted from an optical transmission node to an optical reception node. The optical reception node monitors detection sensitivity of sampling phase shift for the phase of a signal light component corresponding to any one of the plurality of wavelengths and transmits the information, indicating that the detection sensitivity of wavelength CH4 adjoining the outer edge of the transmission band, out of the plurality of wavelengths, has lowered below a threshold, to the optical transmission node. In response to reception of the information indicating the lowering of the detection sensitivity, the optical transmission node stops wavelength control in the direction of the wavelength CH4 adjoining the outer edge approaching the outer edge.SELECTED DRAWING: Figure 17 |
