Test-station for flexible semi-automatic wafer-level silicon photonics testing

Silicon photonics technologies are a particularly attractive solution for developing low-cost optical interconnects with high performance. Imec is developing a silicon photonics technology platform. Developing this platform requires continuous process optimization and design verification, both of which are enabled by the flexible wafer-level test solution that is presented in this paper. The test station enables semi-automatic optical and electro-optical testing of passive and active silicon photonics components and circuits, including waveguides, fiber grating couplers, photodetectors, modulators, filters etc. The measured insertion loss of fiber grating couplers is repeatable to within 0.07dB (6σ), for photodetector responsivity the repeatability is around 0.02A/W (6σ). Calibration procedures have been designed to ensure the long-term reproducibility of measurement results. This is demonstrated with wafer-level measurement data for fiber grating couplers and photodetectors that were gathered over a five-month period. The reproducibility over this period is 0.8dB for the insertion loss and 0.09A/W for the responsivity measurement.