Optical add-drop multiplexer using optical circulators and photoinduced Bragg gratings

This multiplexer adds to a group of optical signals, whose wavelengths belong to a group of wavelengths ( lambda 1 . . . lambda N) and drop from said group of signals at least one optical signal having a given wavelength, chosen from within the wavelength group and comprises at least one optical circulator (C1, C2) having an input for receiving the group of signals and an output, an optical selection means (MS) coupled, on one side, to the circulator and which comprises at least one photoinduced Bragg grating (R1 . . . RN), said photoinduced Bragg grating being associated with the given wavelength and which can be in a first state, where it reflects the signal having said given wavelength and where it transits signals having a wavelength different from the given wavelength or optionally in a second state where it transmits all the signals, and a means (MC) for the control of said selection means (MS) for placing the grating in said second state, the selection means cooperating with each optical circulator for adding and dropping the optical signal or signals. Application to optical telecommunications.