Perturbation theory of optical fibres with power-law core profile

The characteristics of graded-index optical fibres with power-law core profile and homogeneous cladding have been studied using perturbation theory. Analytical expressions are derived for the cut-off frequency, propagation constant and, in the case of leaky modes, the attenuation coefficient of an arbitrary mode on such a fibre. For the case of monomode fibres, excellent agreement is found with existing theoretical results for the propagation constant of the HE₁₁ mode and cut-off frequency of the TE₀₁ mode.On leave from Department of Physics, IIT, New Delhi, India.