Experimental and theoretical study of optical losses in straight and bent Bragg fibres

The leakage loss in straight and bent Bragg fibres has been studied experimentally and theoretically using five fibres differing in the core diameter, the number of layers in the Bragg mirror and their refractive indices. Simple analytical formulas have been derived within ray-optics theory which describe leakage and bending losses. The optical loss calculated using these formulas agrees well with our experimental data. Analysis of the theoretical and experimental results enables us to assess the effect of parameters of the waveguiding system on the optical loss in straight and bent fibres.