Cascaded silicon-nitride integrated spectrometers for wideband high-resolution spectral interrogation

We report the demonstration of a cascaded configuration to realize wideband high-resolution spectrometers in silicon-nitride for the visible range. The cascaded configuration consists of an arrayed waveguide grating followed by a set of resonators and offers a flexibility to achieve the requirements of different sensing applications. We discuss some of the implementation issues of these structures. A preliminary demonstration shows the capability of such spectrometer devices to achieve ~0.1 nm wavelength resolution over 10 nm bandwidth in a compact device in a mm-scale device.