Waveguide Spectral Lens and Solar Spectrum Measurement in the Visible-Near-Infrared Region

We present a compact spectrometer based on integrated waveguide spectral lenses (WSL). The WSL directly focuses the on-chip dispersed light onto a camera at the designed distance without any free-space optics. Commercial polymer materials are chosen for wafer-scale fabrication with low propagation loss near visible-near-infrared region. Solar spectrum around 600–850 nm is obtained by a broadband WSL. The detailed absorption lines of O2 (A band) are observed by a WSL of fine resolution. The results agree well with the reference from a commercial optical spectral analyzer and the literature.