Abstract: A hybrid spatial and wavelength selector for optical switching matrices includes a guide system defining paths between input ports receiving light waves having diverse wavelengths and at least one output port. Gates on the paths are each opened or closed so that the light waves reaching the output port via the gates which are open are selected according to the input ports which received them and according to their wavelength. The guide system is situated only between the optical gates and the output port and includes a wavelength separation system assigning some of the paths to the light waves according to their wavelength. The selector has applications in fiber optic telecommunication networks.

Abstract: An optical demultiplexing system demultiplexes a multiplex which has at least three levels of granularity and includes m interleaved bands of wavelengths each of which includes p wavelengths. The system includes a 1-to-m deinterleaving demultiplexer for demultiplexing the multiplex into m bands of wavelengths and a 1-to-p deinterleaving demultiplexer for demultiplexing each of the m bands into p wavelengths. The numbers m and p are mutually prime.

Abstract: A device for erasing overhead modulation of an optical signal, wherein said optical signal is injected into an optical device able to modulate the optical signal (for example a semi-conductor optical amplifier driver by a bias control) and for which one an automatic gain control does not need to detect the residual overhead modulation, is characterised in that said bias control means applies to said amplifier a compensation voltage presenting a modulation out of phase with respect to said overhead modulation, and in that modulation index of said compensation voltage is (substantially) proportional to the modulation index of said optical signal.

Abstract: A switch for an optical transmission network using wavelength division multiplexing has p1 input ports receiving p1 wavelengths and first switching means for switching the p1 wavelengths to p2 output ports, q1 input ports receiving q1 bands of wavelengths and second switching means for switching the q1 bands to q2 output ports, r1 input ports receiving r1 groups of bands and third switching means for switching the r1 groups of bonds to r2 output ports. The three switching means consist of a single switching matrix adapted to couple any of the p1+q1+r1 input ports to any of the p2+q2+r2 output ports. This single-matrix architecture can switch all the granularities at the same time, which facilitates reconfiguration as a function of evolution of the traffic to be switched.

Abstract: In particular for selectively dropping and/or inserting channels of a wavelength division multiplex, while minimizing losses, the apparatus includes n stop filters and optical switching means provided with n+1 inlet ports of ranks 0 to n, and n+1 outlet ports of ranks 1 to n+1, as well as a set of waveguides making it possible to couple each outlet port selectively to one of said inlet ports of lower rank. Each filter is provided with first and second opposite ports coupled respectively to an associated outlet port and to an associated inlet port of the same rank. Application to optical transmission, in particular for performing routing operations.