Add-drop optical multiplexer comprising optical circulators and photoinscripted Bragg-gratings

The multiplexer includes an optical circulator which has an input connected to a receiver and an output. An optical selector is connected at one side to the circulator and includes at least one photoinduced Bragg grating. The Bragg grating is associated with the wavelength and has a first state where the reflected signal has a predetermined wavelength. Signals having a different wavelength are transmitted. In a second state, all signals are transmitted. A selection control device allows the Bragg grating to be switched into the second state. The selection control device cooperates with each optical circulator for add or drop operation.