Configurations for an interferometric device used for multiplexing and de-multiplexing light are disclosed. The interferometric device may include a first input waveguide, a second input waveguide, an interferometric waveguide, and an output waveguide. A fundamental mode of light may be launched into the first and second input waveguides, and the interferometric waveguide may receive the fundamental mode and generate a higher order mode of light, where the two modes of light may be superimposed while propagating through the interferometric waveguide. The two modes of light may be received at an output waveguide that collapses the two modes into a single mode. The light propagating through the interferometric device may be used for increasing optical power even though the wavelengths of light may be different from one another. Additionally, the interferometric device may reduce coherent noise.