Demonstration of a compressive-sensing Fourier-transform on-chip spectrometer.

We demonstrate compressive-sensing (CS) spectroscopy in a planar-waveguide Fourier-transform spectrometer (FTS) device. The spectrometer is implemented as an array of Mach-Zehnder interferometers (MZIs) integrated on a photonic chip. The signal from a set of MZIs is composed of an undersampled discrete Fourier interferogram, which we invert using l₁-norm minimization to retrieve a sparse input spectrum. To implement this technique, we use a …