PRODUCTION OF OPTICAL WAVELENGTH CONVERTING ELEMENT

摘要

PURPOSE:To improve remarkably the coupling rate of a light incident part and optical waveguide part in particular by adding a stage for a heating treatment to smooth the shape of a refractive index distribution between a stage for the 1st ion exchange and a stage for the 2nd ion exchange of an LiNbO3 substrate in producing a wavelength converting element of IR laser light. CONSTITUTION:The 1st ion exchange for forming an incident part 6 of incident light 4 shown by an arrow on the LiNbO3 substrate 1 is executed for about 60min in a benzoic acid kept at 200 deg.C and thereafter an ion exchange part 7 is formed. The substrate 1 is heat-treated for 60min at 300 deg.C in air to change the refractive index distribution formed to the part 7 to a gentle shape so that the exchange part 7 is changed to an exchange part 8. The substrate is then treated fir 11min in the benzoic acid kept at 230 deg.C and the 2nd ion exchange to form an optical waveguide 5 is executed, by which the element capable of converting the wavelength of the IR laser light to visible light or RV light is obtd. The coupling efficiency to the optical waveguide is thus remarkably improved from the conventional 30%-80% by adding the heat treatment stage.