PRODUCTION OF OPTICAL WAVEGUIDE

摘要

PURPOSE:To decrease the coupling loss of an optical fiber and to obtain an optical waveguide having high quality by applying a diffusion material which changes the refractive index of a crystalline material when diffused to the outside periphery of the columnar crystalline material and diffusing the same by heating. CONSTITUTION:The diffusion material 5 of MgO which decreases the refractive index of the circular columnar LiNbO2 single crystal body 4 having 50mu diameter by diffusion is uniformly deposited by evaporation on the peripheral face of the crystalline body 4 and is heated in a high temp. furnace, by which said material is diffused into the crytalline material 4. The heating is stopped before the diffusion material arrives at the crystalline material. The central part 4 where the refractive index is higher than the refractive index of a diffused layer 6, therefore, forms an optical waveguide which is the pure crystal part without contg. the diffusion material. The waveguide which is high in quality and is nearly complete roundness is thud obtd. The coupling loss in the stage of coupling of the optical fiber is thus decreased.