Accurate multi-region wavelength calibration method for the spectrometer

Abstract

Wavelength calibration is a crucial step in the practical application of the spectrometer. The relationship between wavelength and pixel position on the detector can be determined through characteristic spectral calibration. To apply the spectrometer to multi-channel spectral detection and other applications, we propose a method of multi-regions characteristic spectral calibration on a self-developed spectrometer by introducing a multi-core optical fiber. Experiments are carried out on the self-developed spectrometer with a spectral band of 537 nm ~ 600 nm and a resolution of 0.07 nm. The wavelength and pixel position are accurately matched through third-order polynomial fitting, with a fitting error of ±0.002 nm, improving the precision of the spectrometer in multi-channel measurement applications. At the same time, the spectral nonlinearity of the fitted polynomial is analyzed, and the results show that the spectral nonlinearity is about ±0.6 nm. Additionally, characteristic peaks of each region are fitted to calculate the resolution of the spectrometer. The results indicate that the spectrometer has a resolution of approximately 0.07 nm.