Sub-pixel Algorithms on Linear-array Detector Grating Spectrometer

The spectrum of Gauss apodized fiber Bragg grating (FBG) is analyzed by using transfer matrix method, and the basic principles of sub-pixel curve fitting algorithms including mass center, Gauss and full-width-at-half-maximum (FWHM) are discussed. Based on this, simulation and experimental results are given to compare the three curve fitting algorithms. The results reveal that in simulation, mass center fitting method with an accuracy of 13pm while in experiment, FWHM fitting method with an accuracy of 23pm provides a better match to the actual curve. The research achievements have been applied on the prototype of linear-array detector grating spectrometer and have potential market in portable FBG interrogation field.