A method for synchronizing optical signals conducted via different optical waveguides to an optical network node, wherein the variations in propagation time of the optical signals are compensated by adjustable optical delay circuits of a synchronizing device. To set a new delay for one of the optical waveguides, one of the adjustable delay circuits, already switched into the passive state, is set at the desired delay. This delay circuit is then switched into the active state by means of a high-speed optical switch, and the previously active delay circuit is switched into a passive state.