Light-induced self-written three-dimensional optical waveguide

Three-dimensional (3D) optical waveguides were fabricated in a photopolymerizing resin mixture solution by using a multimode optical fiber, without any moving parts. The core portion has formed by the selective photopolymerization of a higher refractive index monomer by ${\mathrm{Ar}}^{\mathrm{+}}$ laser irradiation through the optical fiber. A continuous, straight waveguide was grown by the self-trapping of a guided laser beam. We demonstrated automatic 3D optical circuit formation that enables regrowth after passing through thick transparent glass plates. This growth mechanism also enables automation of the optical interconnection and packaging process, and could potentially contribute to future expansion of optical fiber communications networks.