1. A method of generating a reconstructed optical spectrum from light radiated from a source and incident on a static multimode multiplex spectrometer, the method comprising: determining a calibration data set that compensates for nonlinear dispersion associated with an optical system of the spectrometer based on an expected spectral response of light radiated from a calibration source and incident on the spectrometer, wherein the determining the calibration data set comprises: producing a calibration mask image at the detector array responsive to the light radiated from the calibration source; electronically processing the calibration mask image to generate a calibration spectral image, wherein said calibration spectral image comprises a matrix of wavelength-specific intensity values associated with the calibration source; and for each of two or more rows of the matrix, identifying two or more peak values and fitting a curve to the identified peaks to determine a functional relationship between wavelength and the pixels of the row; determining a correction mask that compensates for a non-ideal response of a propagation kernel of an optical system in the spectrometer; producing a dispersed mask image at a detector array of the spectrometer by applying the propagation kernel to the incident light; and electronically processing the dispersed mask image based on the correction mask to generate the reconstructed optical spectrum with reduced spectral artifacts.