Single Mode, Air-Cladded Optical Waveguides Supported by a Nano-Fin Fabricated with Direct Laser Writing

Single-mode, air-cladded optical waveguides have wavelength scale diameters, making them very fragile and difficult to handle yet highly desirable for sensing inter-chip photonic interconnects. These contradictory qualities are resolved in this work by supporting the waveguide with a nano-fin structure attached substrate, narrow enough sufficiently tall minimally impact wave-guiding metrics of solid core while providing structural mechanical integrity. The design considerations nano-fin-supported its realization using commercial direct laser writing system based on two-photon activation photopolymer is reported herein. 3D printed characterized experimentally assessed, demonstrating low birefringence an estimated propagation loss LP01x LP01y 2.9 dB/mm 3.4 dB/mm, respectively, attributed surface roughness relatively high refractive index contrast air.