| 摘要 |
PURPOSE:To manufacture a spherically pointed optical fiber having high coupling efficiency with good reproducibility and controllability by sticking a high- refractive index liquid having a dopant of a high diffusion rate to the top end of an optical fiber, heating indirectly said part to a spherically pointed shape and changing continuously the refractive index distribution in the spherically pointed part. CONSTITUTION:The optical fiber 1 is inserted into the high fractive index liquid 11 filled into a vessel 10 so that the liquid 11 sticks near to the top end thereof. The optical fiber 1 stuck with the liquid 11 is then inserted into a vessel 8 and the vessel 8 is heated by the flame of a burner 4 while the fiber is held fixed in the space to heat indirectly the top end and to work the top end to a spherical or tapered shape. Alkaline metallic ions diffuse and penetrate quickly into the fiber 1 when an aq. soln. of alkaline metallic silicate is used for the liquid 11. The refractive index is then distributed so as to decrease continuously from the outside surface toward the inside, by which the coupling efficiency to the optical fiber of a semiconductor light emitting element is improved and Fresnel reflection is prevented. |
