Two-Layer Single-Crystal Fibers Grown By Stepanov's Method

Results on the growing of single-crystal sapphire and heavy metal halide fibers from the melt by Stepanov's method (capillar technique) are reported. In order to minimise the optical losses due to surface imperfections single-crystal halide graded-index fibers with the total diameter between 0.2 and 1.2 mm and length up to 7-8 m were grown. The pre-sence of a crystalline cladding allowed to lower the surface scattering losses of graded-index fibers down for 5-10 times in comparison with unclad fibers.