Laser wavelength control in a WDM system

A transmitter (11) by a single wavelength optical signal, and by WDM network, transmitting the signal (13) and composite multiplex signal channel wavelength. The receiver (12) is band-pass filter selecting, single wavelength optical signal from the composite multiplex signal (21). The wavelength with detector (15) is signal conversion and communication load density of the vibration amplitude exchange with a receiving, determining feedback signal. Adhesive, wherein the backward groove (16), loop to the feedback signal to a transmitter (11) and is used for adjusting the single wavelength optical signal the wavelength.