Low-loss single-mode polymer optical waveguide with perfectly circular cores

We experimentally demonstrate that the Mosquito method is capable of fabricating single-mode polymer optical waveguides with multiple cores while maintaining an identical mode-field diameter among them. The Mosquito method we developed is a technique to form circular cores in polymer waveguides using a commercially available microdispenser and multi-axis syringe scanning robot. However, the core shape tends to deteriorate from a circle because of the monomer flow due to the needle scan. We also demonstrate both theoretically and experimentally for the first time in this paper that the needles with a tapered outer form or just titled straight needles enable to form cores with a high circularity even if those cores are dispensed on any heights from the substrate surface.