Low-loss polymeric optical waveguides using electron-beam direct writing

Low-loss optical waveguides based on a negative tone epoxy Novolak resin polymer have been fabricated using electron-beam direct writing. This polymer has a high refractive index, high sensitivity, large hardness, and T_g>200°C. For single-mode channel waveguides with upper claddings, the propagation losses measured were 0.22 and 0.48 dB/cm at 1330 and 1550 nm, respectively. For waveguides without upper claddings, the losses were 0.5 dB/cm at both wavelengths. The stability of these waveguides was also investigated, and no significant change was observed after 200 h at 90°C and 95% relative humidity.