The invention describes an integrated-photonics arrangement, implementable in a multi-guide vertical integration structure composed from III-V semiconductors and grown in one epitaxial growth run, that allows for vertical and lateral splitting of optical signals co- or bi-directionally propagating in the common passive waveguide into plurality of the vertically integrated passive or active wavelength-designated waveguides, therefore, enabling the wavelength-designated waveguides operating in different wavelengths to be monolithically integrated onto the same substrate and connected to the shared passive waveguide. In the exemplary embodiments of the invention, two active wavelength-designated waveguides, each of which either laser or photodetector, are vertically integrated with a common passive waveguide connected to the input/output optical port shared by both operating wavelengths, to form a single-fiber, two-wavelength receiver (both wavelength-designated waveguides are waveguide photodetectors) or transmitter (both wavelength-designated waveguides are edge-emitting semiconductor injection lasers) or transceiver (one wavelength-designated waveguide is waveguide photodetector and the other--edge-emitting semiconductor injection laser). Advantageously to the previous art, the proposed vertical splitting and lateral routing allows for a reduced footprint size while greatly improving design flexibility and/or device performance.