Flexible Polymer Waveguides With Integrated Mirrors Fabricated by Soft Lithography for Optical Interconnection

Flexible polymer waveguides with integrated 45 ^° mirrors to support surface normal optical coupling for optical interconnection were fabricated using a vacuum assisted microfluidic (VAM) soft lithographic technique. Waveguide array structures with slanted surfaces of the SU-8 master were realized by prism-assisted inclined UV lithography. The internal surface reflected UV light was utilized to eliminate undercut structures and to form the inclined surfaces on both ends of the straight waveguide structure via one-step UV exposure. Varying the inclined surface depth can result in different needed light coupling efficiency. A polydimethylsiloxane (PDMS) mold was subsequently created. The use of UV curable resins in the VAM fabrication resulted in the polymer waveguides with 45^° integrated mirrors, demonstrating a coupling efficiency of 75% for full mirrors and 38% for half mirrors.