Replicated polymeric optical waveguide devices with large core connectable to plastic optical fiber using thermo-plastic and thermo-curable resins

Polymeric optical waveguide (POW) devices connectable to plastic optical fibers (POFs) fabricated by hot embossing using thermo-plastic resin are presented. Optical waveguides with large core sizes of 500 and 1000 μm were fabricated, and a low propagation loss of ∼ 0.2 dB/cm at 650 nm was achieved. A thick photoresist original master to obtain a stamper for hot embossing was fabricated by photolithography with a photoresist. Using photomasks with different patterns, POW device structures were fabricated. Two POW device structures are realized: one is a passive alignment structure and the other is a Y-branch-type POW. By passive alignment structure, POWs directly connected to POFs were realized, and the coupling loss from POF to POF through POW was measured to be 1.6 dB at an optimum core width of 900 μm for 980-μm core size POFs. Y-branch-type POWs with large core size of 1000 μm, branching angle from 2° to 10°, and branching top part radius of 200 μm were fabricated. An output power ratio of 1:1 from each output port was realized. A compact-size Y-branch-type waveguide device was also proposed. POWs with high thermal resistance of more than 200°C were also realized by hot replication using thermo-curable multifunctional methacrylate monomers.