Disclosed are optical-routing boards for opto-electrical systems having optical waveguides embedded in non-laminated optical substrates that enable optical signals to be routed among opto-electric components mounted on the top surfaces of the optical substrates. Methods for making the optical-routing boards are also disclosed. The waveguides are formed by focused pulse-laser writing, with the focal point of the pulsed-laser beam being moved in a three-dimensional manner through the non-laminated substrate. Bevel surfaces are preferably formed in the substrate to facilitate bending of the waveguides.