The invention relates to a system for sending data in an optical network comprising source nodes (1-1, 1-2, 1-3, 1-4, 1-5), each capable of generating, in a spectral band that is associated with it, a multi-carrier optical data signal obtained by modulation of a source signal at a source wavelength and of sending this signal in the form of single-band data bursts (11-13, 21-23, 31-33, 41-43, 51-53) that can be associated with distinct source wavelengths, and a combiner (1,2) for combining single-band data bursts, sent by the source nodes in the spectral bands that are associated with them, into multi-band data bursts (61-63, 71-73) occupying a spectral band corresponding to a juxtaposition of the spectral bands associated with the source nodes. In this system, a unit for controlling an instant of sending of said single-band data bursts by the source nodes, implements a control plane taking account of a path time of the single-band data bursts sent by the source nodes to the combiner.