Pump-induced refractive index change in rare-earth-doped fibre

In this paper, we present a theory that enables us to calculate the change of refractive index of a rare-earth-doped fibre as a function of pump power or signal power. Experimental results carried out in Erbium-doped fibre confirms the accuracy of this theory. Both theoretical and experimental results show that significant index changes can be obtained in the order of 1 to 2mW of optical pump or signal power.