Open-Source Toolbox for Photographic Characterization of Optical Propagation

An alternative method for characterizing optical propagation in photonic integrated circuits based on imaging of scattered light is presented and demonstrated for the spectral range of 450-980 nm. The method is applied to waveguide structures of varying widths and is found to be independent of the input coupling. Propagation losses as low as 1.4 dB/cm are measured for spiral alumina waveguides. Using a tunable laser the optical losses are also determined for AlGaAs-on-insulator waveguides at 910-980 nm wavelengths and are compared to cut-back measurements. An open-source toolbox is introduced, allowing for reliable processing of data and estimation of optical propagation losses.