A Review on 3D Integrated Approaches in Multimode Optical Polymeric Waveguide Fabrication

The missing link in bringing fiber optic and long-haul optical data transmission to chip level is the optical interconnection technology in backplanes and packaging modules. In recent years, much novel research on the fabrication methods has been published. This paper provides a review on the processes and materials; and looks into the technical feasibility and issues in leveraging additive processes to fabricate 3D optical waveguides in flexible substrates. Material selection is emphasized for thin substrate materials such as polyimide and commercial grade waveguide materials are reviewed. The potential of high density optical interconnect using 3D processes such as stacking and folding and additive material deposition approaches such as printing is reviewed, while several methods are looked at for micro-channel fabrication. At the end of the review, a novel methodology is recommended to fabricate 3D optical waveguides on a flexible substrate.