Abstract:
Disclosed is a method of forming a doped glass article. Heated glass particles are deposited on a mandrel where they adhere together to form a porous glass preform having interconnective pores. The mandrel is removed to form a tubular preform having an axial aperture. The preform is suspended in a consolidation furnace by a gas conducting handle having a dopant containing chamber. As the handle and preform are heated, there is flowed through the chamber a gas that reacts with the heated dopant to form a reactant gas that flows into the aperture and into pores, whereby a dopant is incorporated into the porous glass preform. The doped preform is heat treated to consolidate it into an elongated non-porous glass body containing the dopant. The glass body can be provided with cladding glass and drawn into an optical fiber.
Abstract:
In accordance with the present invention, the dopant within one gradient index optical element has two independent concentration distributions. Particularly to use the present invention to obtain a gradient index optical element having an excellent chromatic aberration correction ability, it is only needed to make such dopant distributions as shown in the previously stated Japanese Patent Application No. 280897/1989. However, as to the doping of a dopant into a porous body, there is a limit in the amount which can be doped. This is a disadvantage of the molecular stuffing method, but the reason for this is that the dopant must be supplied into the holes as a solution and it is largely restricted by the solubility of the dopant in the solvent. In addition, since the intra-hole fixing of the dopant depends on the solubility difference by temperature or that by solvent exchange, it is further restricted. For this, the latter process which is an application of the molecular stuffing method preferably takes the distribution that has less doping amount.Accordingly, a large concentration distribution must be provided to the dopant in the preceding process. For that, the preceding process is desirably a gel which has sufficiently large concentration gradient by the sol-gel method. However, the sol-gel method also has a defect, in which the distribution provision relies on the elution of the dopant metal, and thus a convex distribution is easier to produce in principle.In view of the foregoing, it is the most effective that the concentration gradient of the first dopant is formed in a convex shape by the sol-gel method using alcoxide as the raw material for retreiving the first dopant, and that the concentration gradient of the second dopant is formed in a concave shape by an application of the molecular stuffing method.
Abstract:
A process for easily producing a silica glass plate having an internal refractive index distribution suitable for a planar optical waveguide involves carrying out the following steps.(a) A porous silica gel plate produced by a sol-gel method is kept in a reactor, the pressure of which is reduced to a substantially vacuum state.(b) Germanium tetrachloride gas is introduced into the reactor at a partial pressure appropriate to establish an absorption equilibrium between a desired concentration of germanium tetrachloride in said porous silica gel plate and a partial pressure of germanium tetrachloride introduced.(c) The partial pressure of germanium tetrachloride in step (b) is reduced so as to desorb germanium tetrachloride from the surface of the porous silica gel plate.(d) The porous silica gel plate having a described concentration distribution is brought into contact with water within or outside the reactor so as to fix the distribution.(e) The porous silica gel plate is calcined at a temperature of not less than 900.degree. C. to render it nonporous.
Abstract:
A sol-gel method of preparing doped glass articles is provided. The glass is formed by preparing a sol solution containing hydrolyzed silicon alkoxide and ultrafine particle silica. The sol solution can also include a dopant. The sol solution is gelled in a container, dried and sintered to yield the doped silica glass articles.
Abstract:
A process for producing a glass fiber light conductor which has increased tensile strength characterized by forming a protective layer at an elevated temperature either on a preform of the fiber and cladding or on the cladding of a drawn fiber with the material of the protective layer having a coefficient of thermal expansion, which is lower than the adjoining glass material of the fiber so that on cooling from the elevated temperature, the layer is subjected to compressive stresses to increase the tensile strength of the fiber.
Abstract:
An electric current is passed by means of electrode means through a body of molten glass which is maintained at a temperature above its softening point and is flowing in contact with the electrode means to be spun continuously into a glass filament, whereby a modifying oxide is caused to have its ions undergo ion-exchange with ions which can increase or decrease the refractive index of the glass through the ion-exchange and are provided by the electrode means or is caused to undergo electrolysis by the electric current. The ion-exchanger or electrolysis is so controlled that a distribution of refractive index in which the refractive index of the glass decreases continuously from the center line and toward the outer surface of the filament is established within the filament.
Abstract:
A method of forming an article such as a light focusing fiber waveguide by applying to a substantially cylindrical starting member a layer of soot having a radially varying composition by means of flame hydrolysis. The starting member is removed and the resulting substantially cylindrical hollow cylinder is heated and drawn to reduce the cross-sectional area and to collapse the hole to form a fiber having a solid cross-sectional area with a radially varying composition.
Abstract:
A side of a polygonal cross-sectioned glass laser rod core may be clad by applying a slab of a suitable cladding glass material thereto. The fusing of the slab to the core without the formation of entrapped gas bubbles therebetween is accomplished by allowing the slab to rest in essentially line contact with the side of the core at the end adjacent a suitable drawing furnace. The other end of the slab is spaced away from the core material. Means is provided for urging the slab of cladding material toward the side of the encore such that as the core and cladding material are drawn within the drawing furnace, the line of contact between the core and cladding gradually traverses the length of the core and cladding thereby forcing any gas out of the space which exists between the core and cladding to provide a bubble-free interface in the resulting clad glass laser rod.
Abstract:
Ultralow expansion titania-silica glass. The glass has high hydroxyl content and optionally include one or more dopants. Representative optional dopants include boron, alkali elements, alkaline earth elements or metals such as Nb, Ta, Al, Mn, Sn Cu and Sn. The glass is prepared by a process that includes steam consolidation to increase the hydroxyl content. The high hydroxyl content or combination of dopant(s) and high hydroxyl content lowers the fictive temperature of the glass to provide a glass having a very low coefficient of thermal expansion (CTE), low fictive temperature (Tf), and low expansivity slope.
Abstract:
[PROBLEM] There is provided a broadband infrared light emitting device that radiates infrared light having a band broader than a conventional broadband infrared light emitting device.[MEANS FOR SOLVING] The broadband infrared light emitting device at least includes: a light source 4 that emits first excitation light λ1 in a first wavelength range; a first glass phosphor 51 that has an excitation band in a first wavelength range, and when the first excitation light λ1 is incident thereon, emits second excitation light λ2 in a second wavelength range and first infrared light λ3 in a third wavelength range; and a second glass phosphor 52 that has an excitation band in the second wavelength range and does not have an excitation band in the third wavelength range, and when the second excitation light λ2 is incident thereon, allows the first infrared light λ3 to pass therethrough and emits second infrared light λ4 in a fourth wavelength range, and the broadband infrared light emitting device radiates broadband infrared light including at least a part of the third wavelength range and at least a part of the fourth wavelength range to an outside of the broadband infrared light.