Abstract:
In general, in one aspect, the disclosure features a fiber waveguide having a waveguide axis, including a core extending along the waveguide axis and a confinement region extending along the waveguide axis surrounding the core. The confinement region includes a periodic structure along a radial direction extending from the waveguide axis and each period in the periodic structure includes a layer of a chalcogenide glass and a layer of a polymer.
Abstract:
The present invention concerns a preform for an optical fiber, an optical fiber so obtained and methods for making the same. The fiber is characterized in that porous glass doped with at least one dopant is used. Resulting fibers can be used to make high attenuation fibers.
Abstract:
High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.
Abstract:
High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.
Abstract:
A crucible adapted for use in formation of a silicon crystal comprises a crucible wall including a bottom wall and a side wall. An inner layer is formed on an inner portion of the crucible wall and has distributed therein a crystallization agent containing an element selected from the group consisting of barium, aluminum, titanium and strontium. The crucible is made by forming a bulk grain layer on an interior surface of a rotating crucible mold, generating a high-temperature atmosphere in the crucible cavity, and introducing inner grain and crystallization agent into the high-temperature atmosphere, fusing the inner grain to form a doped inner layer. The inner layers of crucibles disclosed herein are adapted to, when heated, crystallize according to any of three operating modes that retain a smooth inner surface and reinforce the structural rigidity of the crucible walls.
Abstract:
A non-porous, transparent glass-ceramic body that is consolidated from a predominately silica-based preform (SiO2+GeO2 85-99.0 wt. %) containing rare earth fluoride crystals embedded within by solution chemistry. The glass ceramic body is suited for making fibers for optical amplifiers.
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 method for continuously melting a glass by means of a high-frequency electromagnetic field in a melting tube is provided. In this technique, the electromagnetic field is coupled in the melt by means of a coil present within a cooling jacket surrounding the melting tube. A grounded screen and a tube of insulating material are present between the wall of the melting tube and the coil. The melt traverses a heating zone and a refining zone, and a solid elongated body is withdrawn from the bottom of the melting tube.