Ultraviolet defined selective in-diffusion of organic dyes in polyimide for applications in optical interconnection technology

Abstract

We report here, for the first time, a novel ultraviolet (UV) defined selective in-diffusion technique for refractive index alterations in a BTDA-alkylated diamine type of preimidized polyimide film. This has been achieved by in-diffusing disperse red 1 (DR1) dye into the polyimide film from an organic solvent-based solution. UV photocrosslinking of the polyimide chains was observed to significantly suppress the in-diffusion of DR1 and provided the means for selective doping of this dye in the polyimide film. This technique is amenable to a laser direct write maskless approach for applications in integrated optics. We have demonstrated this technique by fabricating a low-loss (<0.5 dB/cm) embedded polyimide channel waveguide.