On-chip Spectrometer based on Al₂O₃ Arrayed Waveguide Gratings in the UV-blue Range

Arrayed waveguides gratings (AWGs) are among the most common technologies in wavelength division multiplexing (WDM) and have promising applications in<br/>telecommunication and sensing. These devices are typically realized in material<br/>platforms such as silicon-on-insulator (SOI) and silicon nitride (SiN). With the emergence of material platforms that support low-loss propagation in the ultraviolet wavelength range, demonstrations of devices operating at these wavelengths are a subject of interest. Al₂O₃ is one of the materials that is studied in the context of integrated photonic circuits that target UV wavelengths. In this paper, we propose based on simulations, promising Al₂O₃-based AWGs for the development of a UV-blue (340-480 nm) spectrometer. The devices are fully etched and are designed at wavelengths of 369 and 452 nm. Here, 4- and 8-channels AWGs are proposed with corresponding wavelength channel spacing<br/>of 2.5 and 5 nm. Insertion losses range from 3 to 6 dB. We believe that these AWGs could pave the way towards potential medical applications in UV-VIS spectroscopy, biosensing and bioimaging.<br/>