A reconfigurable optical device for wavelength-division multiplexing networks, comprising two waveguides (A, B) parallel to each other, with two-dimensional confinement, coupled by a bi-directional coupler (C), suitable to selectively drop one and only one of the channels composing the Wavelength-Division multiplexing signal (WDM); the device is reconfigurable as, by appropriately varying the wavelength of the combined pumping beam inside a first waveguide (A), any channel forming the WDM signal can be dropped.