Dispersion in graded-index W-type fibres

A fast and accurate method to obtain dispersion-free propagation at different operating wavelengths in W-type optical fibre with a parabolic-index core is discussed. This is achieved by changing the thickness of the inner cladding and the refractive index of the outer cladding. The results are obtained using a constrained variational method. © 1991 Taylor & Francis Ltd.