A structure for collecting light, comprising several modules (1, 2, 3...), and each module comprising: - a substrate; - elementary light collectors which are juxtaposed on the substrate; and - a waveguide mesh which is carried by the substrate, and which optically connects each elementary light collector of the module (1, 2, 3...) to an optical output (S 1, S 2, S 3...) of said module, so that when a light beam is incident onto the structure, an elementary part of the beam which is collected by any one of the elementary light collectors of the module is transmitted to said optical output of the module via the waveguide mesh, wherein, for each module (1, 2, 3...), the waveguide mesh has a fractal arrangement of division between the optical output (S 1, S 2, S 3...) and the elementary light collectors of said module, in a direction of observation going from said optical output towards the elementary light collectors, the structure further comprises a main optical coupler with several inputs and a single output (S 0), the optical output (S 1, S 2, S 3...) of each module (1, 2, 3...) being optically connected to one of the inputs of said main optical coupler separately from the other modules by a respective optical transfer path (1C, 2C, 3C...) which comprises a phase modulator, and the structure further comprises, for each phase modulator, an electrical modulation signal source which is connected to a modulation input of said phase modulator, so that the optical transfer paths (1C, 2C, 3C...) transmit to the main optical coupler respective parts of the light beam incident onto the structure, in accordance with phase shifts which are produced by the phase modulators, the electrical modulation signal sources being arranged to, during a synchronisation search sequence, simultaneously vary all the phase shifts so as to scan variable combinations of values for all said phase shifts, and the structure being characterised in that it further comprises: - a synchronisation detection system, which is arranged to detect, during the synchronisation search sequence, a synchronisation instant at which the output (S 0) of the main optical coupler transmits a light power which is maximum; and - a selection system, which is adapted to select the values of the phase shifts as existing at the synchronisation instant, and to control, after an interruption of the synchronisation search sequence, an operation of the electrical modulation signal sources where the phase shifts produced by the phase modulators conform to the selected values. - a substrate; - elementary light collectors which are juxtaposed on the substrate; and - a waveguide mesh which is carried by the substrate, and which optically connects each elementary light collector of the module (1, 2, 3...) to an optical output (S 1, S 2, S 3...) of said module, so that when a light beam is incident onto the structure, an elementary part of the beam which is collected by any one of the elementary light collectors of the module is transmitted to said optical output of the module via the waveguide mesh, wherein, for each module (1, 2, 3...), the waveguide mesh has a fractal arrangement of division between the optical output (S 1, S 2, S 3...) and the elementary light collectors of said module, in a direction of observation going from said optical output towards the elementary light collectors, the structure further comprises a main optical coupler with several inputs and a single output (S 0), the optical output (S 1, S 2, S 3...) of each module (1, 2, 3...) being optically connected to one of the inputs of said main optical coupler separately from the other modules by a respective optical transfer path (1C, 2C, 3C...) which comprises a phase modulator, and the structure further comprises, for each phase modulator, an electrical modulation signal source which is connected to a modulation input of said phase modulator, so that the optical transfer paths (1C, 2C, 3C...) transmit to the main optical coupler respective parts of the light beam incident onto the structure, in accordance with phase shifts which are produced by the phase modulators, the electrical modulation signal sources being arranged to, during a synchronisation search sequence, simultaneously vary all the phase shifts so as to scan variable combinations of values for all said phase shifts, and the structure being characterised in that it further comprises: - a synchronisation detection system, which is arranged to detect, during the synchronisation search sequence, a synchronisation instant at which the output (S 0) of the main optical coupler transmits a light power which is maximum; and - a selection system, which is adapted to select the values of the phase shifts as existing at the synchronisation instant, and to control, after an interruption of the synchronisation search sequence, an operation of the electrical modulation signal sources where the phase shifts produced by the phase modulators conform to the selected values. - a synchronisation detection system, which is arranged to detect, during the synchronisation search sequence, a synchronisation instant at which the output (S 0) of the main optical coupler transmits a light power which is maximum; and - a selection system, which is adapted to select the values of the phase shifts as existing at the synchronisation instant, and to control, after an interruption of the synchronisation search sequence, an operation of the electrical modulation signal sources where the phase shifts produced by the phase modulators conform to the selected values.