Abstract: Reconfigurable ring transmission network with multiplexing in wavelength for semi-permanent links, the network including at least one ring (10) comprising nodes (12) and at least one optical fiber (18, 20) passing through the nodes, and each site (13) in the network comprises transmission-reception means (EN, ES, RN, RS) for one or more wavelengths and each node comprises optical add-drop means (IN, IS, XN, XS) for this wavelength and optical switching means (CN, CS) to connect these means to the transmission-reception means, the network used for optical telecommunications.

Abstract: This device includes optical add-drop multiplexers (M1 to M2) each having a band-pass filter. An optical switch (C1) has outputs connected to the multiplexers. An optical coupling (C2) has inputs connected to the multiplexers. The device is useful in optical communications.

Abstract: Optical component adapted to monitor a multiwavelength link for use as an add-drop multiplexer in optical networks. The optical component includes an input fiber (68) for transmitting signals of different wavelengths, a diffraction grating (70) for dispersing these signals on several orders of diffraction, fibers (72, 74, 76 and 78) for recovering the dispersed signals corresponding to a given order of diffraction, and fibers (79, 80, 82, and 84) for recovering the same signals but corresponding to another order of diffraction so as to monitor the state of these signals.

Abstract: According to the invention, a first band-pass multidielectric filter (F1) receives optical signals, transmits at least one of them and reflects the untransmitted signals. An adding means (F2) inserts among them at least one other optical signal. A photoinduced Bragg grating filter (R) receives the signals reflected by the first filter and transmits them to the adding means and reflects any optical signal of the same wavelength as the signal transmitted by the first filter and which is liable to exist among the signals reflected by it. Application to optical telecommunications.