High resolution non-scanning spectrometer

An optical spectrometer includes an echelle array disposed in the path of a light signal so as to diffract the incident light signal. The light signal falls within a predetermined wavelength band centered about a central wavelength. The echelle array has a plurality of diffraction scattering sites periodically spaced apart by a distance of at least about five times the central wavelength. The spectrometer further includes a photodetector array positioned to receive a far-field diffraction pattern produced by the diffracted light from the echelle array and to output electrical signals representing the spatial pattern and relative intensity of the far-field diffraction pattern. Additionally, the spectrometer includes a processing circuit coupled to the photodetector array for processing the electrical signals to determine the power spectrum of the light signal. The processor circuit calibrates by measuring far-field diffraction patterns and determining SIRs for light at a plurality of different known wavelengths. When the light signal is projected onto the echelle array, the processing circuit determines the power spectrum by deconvolving the SIRs obtained during calibration from the far-field diffraction pattern measured for the light signal.