The dataset includes detail of fibre treatments with adhesion promoter and the impact of treatment duration on the fibre ends. Then the detail of mechanical properties of polymer waveguides are presented under both transverse misalignment and tensile stress. The effect of photo-bleaching is also investigated when polymer bridges were put under tensile stress. Finally, extra information is presented about millimetre-long waveguides and how the bidirectional curing technique enabled us to fabricate up to 1.2 mm long polymer waveguides. The supplementary materials also include the actual data (Excel files) used to make the graphs in the paper.