The present invention concerns a generator (G1) for generating at least M data carrier optical signals with selectable carrier wavelengths, where M is an integer greater than 1, said generator comprising N laser sources (S.sub.i) with constant and different wavelengths, where N is an integer greater than 1, and an optoelectronic modulator (Mod.sub.1) adapted to form one of said M optical data carrier signals,which generator is characterized in that it includes: M-1 other optoelectronic modulators (Mod.sub.2 to Mod.sub.M) each adapted to form one of said M-1 other optical data carrier signals, and an at least partially broadcasting optical switch (100) having N input ports (PE.sub.i) connected to the N laser sources and M output ports (PS.sub.i) connected to the M modulators, the optical switch being adapted to send to a plurality of modulators an output signal with a selectable carrier wavelength, to form said M signals.