Flexible 3D-printed optical waveguides for photonic networks and multisensing applications

Flexible and low-cost photonic platforms are increasingly important for emerging wearable and environmental sensing applications. Here, we present a flexible 3D-printed optical waveguide platform fabricated using a rapid and low-cost resin-based 3D printing method. The waveguides incorporate built-in fiber alignment holders to enable precise and repeatable coupling with external optical fibers. The printed structures exhibit high transparency and low propagation loss (1.66 dB/cm). The modular design allows individual waveguides to be interconnected, supporting scalable photonic network architectures. We further demonstrate that environmental parameters, specifically temperature, influence the optical transmission of the polymer waveguide, establishing a reference behavior that can be used to calibrate future sensing responses. This work highlights the potential of low-cost, customizable polymer photonics for soft, wearable, and environmentally responsive sensing platforms.