Device for extraction and re-insertion of an optical carrier in optical communications networks

A device for extraction of at least one optical carrier, modulated by an information signal, from a transmission line carrying an optical signal stream including several carriers at different wavelengths, and for reinsertion onto the line of the same carrier modulated by a different information signal, said device comprising:

• at least a first three-port optical circulator with an input port connected to the line to receive an optical signal stream including a carrier to be extracted and an output port connected to the line to send along the line an optical signal stream including a carrier reinserted;
• at least a second three-port optical circulator with an input port connected to means for generating a carrier to be reinserted, and an output port connected to means for receiving the carrier to be extracted;
• and
• at least a bandpass optical filter connected between an input-output port of the first circulator and an input-output port of the second circulator, said optical filter being a finely wavelength-tunable filter capable of transmitting the wavelength corresponding to the passband and reflect all other wavelengths, so as to transfer from the first circulator to the second circulator the carrier to be extracted, and from the second circulator to the first circulator the carrier to be reinserted, and to allow carriers at other wavelengths to pass from the input port to the output ports of the circulators.