Fig. 2.

Packaged dFT photonic integrated circuit (PIC) and spectral basis set. a Schematic diagram of the dFT spectrometer characterization setup; b an exemplary transmission spectrum of the dFT device corresponding to an arm length difference of 0.7 mm; c transmission spectra of the device for all 64 permutations of the switch on/off combinations: the ensemble of 64 spectra constitute the basis set for spectrum reconstruction