CRYSTALLINE FIBER AND ITS PRODUCTION

摘要

PURPOSE:To produce a crystalline fiber having fine core size and sharp refractive index gradient at an interface between a core part and a clad part. CONSTITUTION:Magnesium oxide 12 is deposited on a side face of a lithium niobate fiber 11 to form a base material 10. The base material 10 is heated by gaseous CO2 laser beam 13 while moving the base material 10 to melt a part which becomes to a clad part to make a molten part 21. The magnesium oxide 12 is diffused into the lithium niobate fiber 11 at the molten part 21, and a part in which the molten part 21 is cooled and solidified becomes to the clad part low in refractive index and the part which is not molten and composed of only lithium niobate fiber 11 becomes to the core part, and crystalline fiber is formed.