Method for setting the wavelength of the zero crossing of the chromatic dispersion of compensated monomode fibres by rounding the refractive index profile

摘要

The invention relates to a method which permits exact setting of the wavelength of the zero crossing of the chromatic dispersion of compensated monomode fibres to be carried out without placing strict requirements on the manufacturing tolerances. According to the invention, in a first operation a monomode fibre is produced in such a way that the compensation of the material dispersion by an oppositely directed waveguide dispersion leads to a zero crossing of the resulting chromatic dispersion which is at a wavelength slightly shorter than the desired wavelength. After a possible application of protective lacquer, a method which is suitable for controlled rounding of refractive index profiles is used in a subsequent operation to round the refractive index profile (homogeneously over the entire length of the fibre) until the wavelength of the chromatic dispersion zero crossing has shifted towards longer wavelengths onto the desired value, and this can be monitored by measuring during the rounding process, or else after the method has been terminated in the event of quantitative stipulation of the process parameters in order to influence the refractive index profile.