Polymer interposer for efficient light coupling into 3 µm silicon-on-insulator waveguides

The polymer waveguide taper structures are designed for interfacing 3 μm silicon-on-insulator (SOI) devices to standard single mode SM fiber. The structure consists of polymer waveguide with its optical facets compatible with the modes of single-mode (SM) fiber and silicon waveguide. Simulations suggest that the coupling efficiency of -0.63 dB from the SM fiber to 3 μm strip waveguide can be achieved. We show experimentally the transmission loss of 0.6 dB/cm in polymer waveguide and coupling loss of 0.7 dB from the SM fiber to 2.1 μm polymer waveguide.