Simple and reusable fibre-to-chip interconnect with adjustable coupling efficiency

A simple, efficient and reusable fibre-to-chip interconnect is presented. The interconnect is based on a V-groove (wet-chemically etched) in silicon, combined with a loose-mode Si3N4-channel waveguide. The loose-mode waveguide is adiabatically tapered to the integrated optical (sensor) circuitry. This adiabatic taper enables the dimensions of both the integrated optical sensor circuitry and the loose-mode waveguide section to be designed indepently. The coupling efficiency of the ''plug-it-in'' interconnect is tunable between zero and the maximum obtainale value by tightening two adjustment screws. Coupling efficiencies up to 60% using TE-polarized light at wavelength of 632.8 Nn have been reproducibly measured.