Abstract:
Disclosed is a method for fabricating an optical fiber preform using a double torch in MCVD, which includes a first process of heating a quartz tube (10) at a temperature lower than a sintering temperature by using a first torch (21) with putting reaction gas, oxygen gas and dehydration gas into the tube so that soot particles are generated and deposited, and heating the tube to a predetermined temperature by using a second torch (22) spaced apart from the first torch after the first torch (21) passes so that moisture in the soot particles is removed; and a second process of conducting dehydration for removing moisture in the soot particles by use of the first torch (21) again, and heating the tube above a sintering temperature by using the second torch (22) so that the soot particles free from moisture are vitrified.
Abstract:
A method of forming an alkali metal oxide-doped optical fiber by diffusing an alkali metal into a surface of a glass article is disclosed. The silica glass article may be in the form of a tube or a rod, or a collection of tubes or rods. The silica glass article containing the alkali metal, and impurities that may have been unintentionally diffused into the glass article, is etched to a depth sufficient to remove the impurities. The silica glass article may be further processed to form a complete optical fiber preform. The preform, when drawn into an optical fiber, exhibits a low attenuation.
Abstract:
Disclosed is a method of manufacturing an optical fiber perform using MCVD including dehydration and dechlorination, which executes the following process repeatedly with changing the composition of soot generation gas according to the refractive index profile, the process including the steps of: forming a soot layer having pores on an inner wall of a deposition tube at a temperature lower than the soot sintering temperature with putting soot generation gas and oxygen gas into the rotating deposition tube; removing hydroxyl groups with keeping the pores by putting dehydration gas into the deposition tube; removing chlorine impurities existing in the soot layer with keeping the pores by putting dehydration gas into the deposition tube; and sintering the soot layer by heating the deposition tube at a temperature over the soot sintering temperature.
Abstract:
A method of manufacturing an optical fibre, comprises: (i) forming a preform (10) for drawing into the fibre, the preform (10) comprising a bundle of elongate elements (20,50) arranged to form a first region that becomes a cladding region of the fibre and a second region that becomes a core region of the fibre; (ii) drawing the preform (10) into the fibre. The bundle of elongate elements (20,50) comprises a plurality of elongate elements (20) of a lower purity dielectric material and at least one elongate element (50) of a higher purity dielectric material. The first region comprises a plurality of the lower purity elements (20) and the second region comprises the higher purity element (50).
Abstract:
An object of the present invention is to provide a synthetic quartz glass optical material having a high optical transmittance for a radiation 157 nm in wavelength emitted from F2 excimer laser and a high resistance against irradiation of a F2 excimer laser radiation, yet having a uniformity suitable for such a fine pattenring using a F2 excimer laser, and to provide an optical member using the same. The problems above are solved by a synthetic quartz glass optical material for F2 excimer lasers having an OH group concentration of 0.5 ppm or lower, a fluorine concentration of 0.1 to 2 mol%, a hydrogen molecule concentration of 5 X 10 or lower, a difference between the maximum and minimum fluorine concentrations within 20 mol ppm, and a difference between the maximum and minimum refraction indices of 2 X 10 or lower.
Abstract translation:本发明的目的是提供一种合成石英玻璃光学材料,其对于从F2准分子激光器发射的波长为157nm的辐射具有高的透光率,并且对F2受激准分子激光辐射的照射具有高的抗性,但具有适合的均匀性 对于使用F2准分子激光器的这种精细的图案,并提供使用其的光学构件。 上述问题通过具有OH基浓度为0.5ppm以下,氟浓度为0.1〜2mol%,氢分子浓度为5×10 <16λ的F2准分子激光的合成石英玻璃光学材料来解决。 分子/ cm 3以下,最大和最小氟浓度之间的差异在20摩尔ppm以内,最大和最小折射率之间的差异为2×10 -5以下。
Abstract:
The invention relates to a method for economically producing a quartz glass rod consisting of synthetic quartz glass with a radially and axially homogenous refractive index curve. According to the invention, a whole cylinder consisting of quartz glass is coated with a coating tube consisting of porous glass, the latter shrinking onto the whole cylinder during sintering. The coating tube has a predetermined refractive index which ensures that there is a maximum increase in the refractive index value of 0.001 in the area of a contact surface between the whole cylinder and the shrank-on coating cylinder. A solid quartz glass rod produced in this way is characterized by a homogenous refractive index distribution in an axial and radial direction and comprises a whole cylinder consisting of synthetic quartz glass which is encased in a quartz glass layer formed by a coating tube consisting of porous quartz glass that is sintered and shrunk on with a maximum increase in the refractive index of 0.001 in the area of a contact surface. The inventive quartz glass rod is used for economically producing a preform for multimode fiber optical waveguides.
Abstract:
A process for producing a synthetic quartz glass for optical members, which comprises the step of irradiating a synthetic quartz glass having an OH group content of 50 ppm or lower with vacuum ultraviolet having a wavelength of 180 nm or shorter to improve the transmittance in a region of wavelengths not longer than 165 nm.
Abstract:
The invention includes methods of making lithography photomask blanks. The invention also includes lithography photomask blanks and preforms for producing lithography photomask. The method of making a lithography photomask blank includes providing a soot deposition surface, producing SiO2 soot particles and projecting the SiO2 soot particles toward the soot deposition surface. The method includes successively depositing layers of the SiO2 soot particle on the deposition surface to form a coherent SiO2 porous glass preform body comprised of successive layers of the SiO2 soot particles and dehydrating the coherent SiO2 glass preform body to remove OH from the preform body. The SiO2 is exposed to and reacted with a fluorine containing compound and consolidated into a nonporous silicon oxyfluoride glass body with parallel layers of striae. The method further includes forming the consolidated silicon oxyfluoride glass body into a photomask blank having a planar surface with the orientation of the striae layer parallel to the photomask blank planar surface.
Abstract:
A method for producing a preform capable of restricting deformation of each member during a production process, and a method for producing, using the preform, an optical fiber small in polarization mode dispersion. In the method for producing the preform, a collapse process is divided into at least two steps; a first step of forming a first collapse body by the collapse of a core rod member and a first clad tube member and a second step of forming a new collapse body by the collapse of the first collapse body and a second clad tube member. An obtained collapse body is drawn in at least the first step; and such a multi-stage collapse process and drawing of an obtained collapse body can reduce an outer diameter ratio of an outer-side member to an inner-side member to be collapsed and hardly produce deformation that would be caused by heating and the like at one time collapse.