New Fabrication Method of Self-written Waveguide by Using Photosensitive Polyimide

Abstract

A Photosensitive polyimide (PSPI) precursor for light-induced self-written (LISW) waveguide based on a poly(amic acid) (PAA) and 1,4-dihydropyridine derivatives (DHP)s has been developed. The PAA was prepared by ring-opening polyaddition of aromatic fluorinated tetracarboxylic dianhydrides and diamines. Upon exposing the PSPI precursor to laser light, a self-focusing effect induced by the difference in refractive index between the exposed and unexposed portions was observed. Thermal treatment of the laser exposed PSPI precursor gave a polyimide LISW wave guide with no other processing steps. The coupling loss between two multimode fibers with a 0.5 mm gap, was decreased from 5.2 dB in air to 0.7 dB by insertion of the PSPI LISW waveguide. This simple new fabrication method of LISW waveguide structures allows convenient and easy alignment of optical waveguide components.