Światłowód pierścieniowy domieszkowany neodymem.

Signal processing, device oriented, ring-index fibers have a unique capability of transmitting either quasi planar modes for large ring diameters or the second order mode in a quasi single-mode regime at lossy discrimination of the fundamental mode, for small ring diameters. Ring-index fibres can maintain single mode transmission for considerable values of normalized frequency for particular cases of the refractive index profile. Theoretically predicted features of ring index fibres were confirmed experimentally on the samples manufactured by the author. The ring shape of doped rare earth core gives possibility to stimulate luminescence from inside of the fibre. In this paper the ring core doped Nd3+ ions fibre is reported. The analysis of dependences between parameters of core on light propagation in ring-core optical fibers is presented. The ring core is made from silica glasses doped by Nd3+ ions.