FORMATION OF GLASS FILM FOR OPTICAL WAVEGUIDE

摘要

PURPOSE:To obtain the optical device having a small size, low loss and multifunctionality by forming a glass film contg. a dopant for refractive index control having a high refractive index and a rare earth element on the surface of the glass layer of a substrate. CONSTITUTION:The substrate 6 imposed on a lower electrode 4 is heated by a heater 7 and a high-frequency electric power is supplied between the upper and lower electrodes 3 and 4 to generate plasma 5. The inside of a housing 2 is then evacuated to a vacuum by driving of a liquid nitrogen trapping device 21, a rotary pump 22 and a discharge device 23. The vapors generated by tanks 9 to 11 are ejected in a mixed state from a gas ejecting pipe 8 via a valve 12 into the housing 2 where the vapors are blown to the substrate 6. The glass film contg. the dopant for refractive index control having the refractive index higher than the refractive index of the glass layer and the rare earth element is formed on the surface of this glass layer of the substrate 6. The optical device having the small size, low loss and multifunctionality is obtd. in this way.