  The chromatic dispersion curve of the fundamental mode in small core
microstructured fibres (SCMF) is both calculated using a Finite Element Method
(FEM) and measured with a low coherence interferometric method. The great
sensitivity of the chromatic dispersion to variations of the geometrical
parameters of SCMFs (the pitch and the diameter) is pointed out. An excellent
agreement is obtained between the numerical and the experimental results over a
half micrometer spectral bandwidth [1.1 $\mu$m-1.6 $\mu$m].
