SELF-COATED SINGLE CRYSTAL, AND PRODUCTION APPARATUS AND PROCESS THEREFOR

摘要

A self-coated single crystal that without any special step conducted after crystal growth, has its circumference coated with a layer of different properties. There is provided a self-coated single crystal characterized in that in operations comprising melting crystal raw materials for core and clad in a single crucible and carrying out growth of a single crystal through pulling up technique or pulling down technique, grown single crystal in as-growth condition has its circumference self-coated with a clad whose refractive index is lower than that of the core.