Apodisation the grating Apodisation is a process of tapering the strength of the grating at either end so that the apparent Ri change is gradual rather than abrupt. The reflection band of an apodised grating is shown in part (c)of the figureApodisation the grating • Apodisation is a process of tapering the strength of the grating at either end so that the apparent RI change is gradual rather than abrupt. The reflection band of an apodised grating is shown in part (c) of the figure