Patent ID: 7327955

Claim:
A system for switching optical signals with carrier wavelength conversion capacity, comprising a set of input ports, a set of output ports functionally connected to the input ports so that an input signal presented to one of the input ports are selectively routed to at least one of the output ports, and wavelength conversion means providing a capacity for converting an input signal carrier wavelength to at least one other output port output wavelength, said wavelength conversion capacity of said conversion means being limited by at least one of the following three limitation means i) to iii): i) for at least one of said output ports, no wavelength conversion is applied for sending a signal from an input port; ii) for at least one of said output ports, wavelength conversion is applied for sending a signal from an input port, but to only a restricted number of wavelength values from the number L of different wavelength values accepted at the input, this restricted number being greater than 0 and less than L, and iii) for only a restricted number of output ports less than the total number of output ports of the switching system, wavelength conversion is applied for sending a signal from an input port to any wavelength value from the number L of different wavelength values accepted at the input, the system having a number n of input ports and a number n′ of output ports, the numbers n and n′ being equal or different, each input port comprising a spectral multiplex comprising a number L of carriers having L respective wavelengths; wherein the system further comprises: a first buffer stage for imposing a number K of mutually time-shifted copies of each of the n optical input signals, a second stage for converting each of the n*K multiplexes from the first stage into a number of copies less than n′, and a third selection stage for selecting L optical signals from the multiplexes provided by the second stage to an output port.