Fig. 3: Calibration and characterization.
a Schematic of the chaos-assisted spectrometer and the spectral reconstruction process. The zoom-in figure shows SEM photo of the functional region of the fabricated chaos-assisted spectrometer, while the scale bar indicates a length of 10 μm. The yellow dashed line indicates circular shape. b Upper: optical microscopy photo of the fabricated device after Ti heaters and Au interconnection layer deposition. Bottom: Image of the photonic chip wire bonded to a customized PCB board with a fixed fiber-array. c Normalized response matrix obtained by sweeping the heating power linearly from 0 to about 16.5 mW from 1480 nm to 1580 nm with 300 heating channels. d Normalized transmission spectra at 1st and 300th heating channels. Black numbers mark resonance peaks detailed in Supplementary Information Table. S1. e Auto-correlation function where the periodicity level is shown by the black dashed line. f Cross-correlation function. The red line is the average cross-correlation function. Inserted graphs are the cross-correlation functions of three randomly selected transmission groups, designated as green, blue, and yellow. g Spectral correlation function of \(C\left(\Delta \lambda \right)\) around \(\Delta \lambda =0\) where the estimated resolution is illustrated by the black dashed line
