Demonstration of the one-step continuous fabrication of flexible polymer ridge waveguides via nanochannel-guided lithography

We demonstrate a facile one-step fabrication of flexible ridge waveguides by using the nanochannelguided lithography (NCL) that enables continuous extrusion of a polymer that forms waveguiding core ridge on an undercladding polymer substrate. NCL utilizes a well-cleaved mold edge with microtrench patterns to slide continuously over a UV-curable liquid resin-coated substrate under conformal contact, where the resin and substrate can be chosen for suitable waveguide core and undercladding materials. The local heating of a trench mold can control the viscosity of liquid resin for optimal filling into the microchannels followed by smooth extrusion, which is subsequently UV-cured. Such a smoothly extruded resin core exhibits a very smooth surface potentially promising for the low-loss waveguiding operation which was experimentally confirmed by optical insertion loss characterization. The proposed technique may provide a practical route to the continuous and seamless fabrication of scalable waveguides and photonic elements. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.