Improvement of optical and mechanical properties of self-written polymer waveguides attached to optical fibers

Polymer waveguide bridges with high reproducibility up to 750 mu m in length were optically written between two single-mode optical fibers. Fiber ends were treated by adhesion promoter to covalently bond to both the silica fiber and the photopolymer waveguide, the mechanical properties of both long and short bridges were improved. The optical insertion loss was 0.5 dB for the longest waveguide. The mechanical properties and optical transmission of polymer waveguides were investigated under shear and tensile stress. Bi-directionally cured 500 mu m polymer bridges showed average lateral misalignment of 175 mu m before breakage. Fibers treatment also improved adhesion bonding at both polymer/fiber interfaces such that 300 mu m polymer waveguide could endure average longitudinal strain of 23% for photobleached and 32% for unbleached polymer bridges.