Measurements of a semiconductor waveguide using a low-coherence interferometric reflectometer

A low-coherence interferometric reflectometer is studied as a tool to measure both semiconductor waveguide loss and reflectivity. Accurate estimation is given by using the integral values of the interference envelopes observed as reflected power from the sample. This estimation is free of influence from coupling between the sample and reflectometer or dispersion in the semiconductor materials. The experimental results are in good agreement with those obtained by the Fabry-Perot method. The facet reflectivity measured in 0.5-mm-long very short samples shows waveguide thickness dependence agrees with theoretical results. This approach shows good repeatability and accuracy for short samples.