A method is provided for producing a fibered element (FO). The method consists in i) forming an assembly (E) by surrounding a first part (C) of vitreous material, with a second part (G) having first optical properties, ii) then drawing the assembly (E) in a longitudinal direction so as to increase its longitudinal dimension while reducing at least one of its transverse dimensions, this increase and reduction being chosen so as to transform at least certain of the said first optical properties of the second part (G) into second optical properties allowing it to selectively filter, in a direction substantially perpendicular to the longitudinal direction of the drawn assembly, photons of which the wavelengths fall in at least one selected spectral band. |