Polymer-based 3D printed optical waveguides are fabricated and characterized using a low-cost fused deposition modeling (FDM) printer. Waveguides with two different material combinations are printed: Polymethyl Methacrylate (PMMA) as core material with Polylactic Acid (PLA) as cladding material, and Polyethylene Terephthalate Glycol (PETG) as core material and PMMA as cladding material. Several waveguides with different printing parameters were produced and characterized. The adhesion between the filament lines is acceptable to good for both material combinations and all printing parameters with better adhesion for higher extrusion factors. The waveguide cross-sections were analyzed using an illuminating LED, a microscope lens, and a camera. The cross-sections of the waveguides with PMMA core and PLA cladding show fully illuminated core filaments and dark cladding filaments. Some waveguides with PETG core and PMMA cladding show dark core filaments and a high amount of light in the cladding. Air gaps between filament lines are seen in the cross-section analysis. They can be reduced but not fully eliminated by optimizing the printing parameters. The attenuation was analyzed with a cut-back method using an LED as a light transmitter, and a photodiode as a receiver. The waveguide attenuation is between 0.78 dB/cm and 1.50 dB/cm with no systematic differences for both material combinations. The highest attenuation is seen where the core is printed as one filament line. The results of these experiments show that 3D printing offers a viable method to produce optical waveguides that can be used as building blocks for optical components or optical sensors.
Kotadiyaa et al. (2025) studied this question.