Abstract: The invention provides an optical multiplexing device comprising: a plurality of optical sources with integrated collimators (31-37) whose output beams are combined by mirrors (41-47) or other beam deflecting elements, which combine the beams into a single composite beam diverging from a common origin point (30). This is done by arranging the mirrors (41-47) staggered at different distances from the origin point, and at different angles to each other taking accourt of the dependence of the beam divergence in far field on the distance from the origin point.