A multimode optical waveguide network comprises a parent waveguide and a plurality of child waveguides. Each waveguide is a multimode optical waveguide having a first surface region, multiple second surface regions, and at least one guiding element attached to a surface of the waveguide or embedded within the waveguide, each second surface region of the parent waveguide optically coupled to the first surface region of a corresponding child waveguide. The guiding element(s) of the parent waveguide is arranged to guide a beam, from or to its first surface region, to or from any selected second surface region of its multiple second surface regions. The guiding element(s) of each of the waveguides is configurable for selecting the second surface region of that waveguide and/or responsive to at least one beam characteristic for selecting the second surface region of that waveguide via modulation of the at least one beam characteristic.