Fig. 5. Further explorations about the programmability, resolution scalability, sensitivity, and thermal stability of the reconfigurable spectrometer.

a Reconstruction accuracy and computing time vs. the channel number. b Spectrometer resolution vs. the channel number, including the experimental results from a 7-stage design and the simulated results from 8- and 9-stage designs. The continuous downward trends reveal the path towards picometer-scale spectral resolution, reaching a same level with commercial bench-top products (YOKOGAWA AQ series47). c The reconstructed spectra of a narrowband signal under different OSNR with aggregated noise. The insets show two spectra of inputs with constant noise floor at −55 dBm. d The measured spectral response of one sampling channel at different temperatures. The insets show the small redshift of the spectral response with increasing temperature