The present invention relates to a method of fabricating a light emitter comprising several sources (S1 to S15) and a support (2). Each source (S1 to S15) is arranged so as to emit a light beam at a working wavelength. For each source, a position (X1 to X15) of this source along a fixing direction (3) is determined, as a function of optical properties of a spectral multiplexer provided so as to be associated with this emitter, of the working wavelength of this source and of a placement of the emitter with respect to the multiplexer. These positions (X1 to X15) are determined so that, when the emitter is associated with the multiplexer, the multiplexer (4) spatially superimposes the light beams. Next, each source (S1 to S15) is fixed, along the fixing direction (3), on the support (2) at its position (X1 to X15) previously determined, so that the sources are distributed according to the law or the properties of chromatic dispersion of the spectral multiplexer. Advantageously, it is possible to fix the sources (S1 to S15) on several parallel fixing axes (13, 14, 15) extending along the fixing direction (3).