Sub-pixel wavelength calibration of spectrometer

Fiber spectrometers have important applications in many areas. In order to obtain accurate measurement results, the wavelength of the spectrometer needs to be calibrated. A fussy but more accurate calibration method is proposed, which uses more than 100 spectral lines from 6 element gas discharge lamps to perform peak coarse positioning, interpolation and peak seeking processing to derive a wavelength correction formula. Compared with the original data, the calibrated wavelength has higher accuracy. After calibrated, the errors are within 0.008 nm if we measure the certain corrected spectral lines. In addition, the error of any wavelength, which is not included in 6-element gas discharge lamp, is less than 0.025nm in the full spectrum range (200nm-1080nm). The results show that the calibration of a large number of standard lines allows the spectrometer to achieve sub-pixel wavelength accuracy. But the overall accuracy improvement is limited.