Tapered waveguide by liquid for a coupler of optical fibers to MEMS devices

We report a tapered liquid waveguide for an optical fiber-to-chip coupler. The tapered liquid waveguide has a smooth surface and has both a large structure and a micro structure on one chip. The waveguide is able to couple optical fibers of large-diameter to small MEMS devices. A Parylene film on the liquid prevented the liquid from deformation and evaporation. We fabricated the silicone oil waveguide by hydrophobicity of CYTOP. We measured a propagation loss of the tapered waveguide by entering the laser beam from the incident face. From a measurement result, this tapered waveguide can be a coupler which connects optical fibers to MEMS devices.