Soft, Side Emitting Optical Fibers by Multimaterial Printing

Side-emitting optical fibers are used to illuminate large volumes of non-transparent material. Introducing a customized side-emission profile is a major challenge in the fabrication of side-emitting optical waveguides, requiring modulation of the guiding and emitting properties along the fiber length. This is particularly difficult to realize in continuous processing of soft materials. In this work we use extrusion-based multimaterial printing to generate segmented hydrogel optical fibers with tailored side emission. We print fibers with segments of different optical properties by switching between a waveguiding ink and its mixture with scattering particles. The method allows printing segment lengths below 500 microns. The length of the segments can be tailored by controlling the switching time between inks during printing, thereby achieving desired side-emission profiles along the fiber length. The presented technology and material combination allows unprecedented flexibility for designing optical fibers with customizable optical properties using simple processes and medical materials.