Wavelength dispersion of the Kerr effect in optical fibres

Abstract

It is important to determine the dispersion of the Kerr effect in optical fibres for application to fibre communication and fibre sensors; little information on this effect presently exists in the literature. The Kerr coefficient K, has been found to vary with material, wavelength, and temperature. The classical Havelock's Law1 has the form of K = c(n2 - 1)2/E2nλ where λ is the wavelength, c is a material constant and independent of wavelength, n is the refractive index, and E is the applied electric field. Havelock's law appears adequate for some materials. It has been verified experimentally by several investigators.2,3 In order to measure the very small Kerr coefficient for silica optical fibres, the experimental arrangement in Fig. 1 was used. The Kerr coefficient K = dI0/IπlE2 can be measured by detecting the parameters dI0, the light intensity variation, I, the total light intensity, E, the applied electric field, and l, the length of the fibre.