Abstract:
This invention relates to a dispersion-compensating fiber which can be drawn at a lower temperature and can further reduce optical transmission loss. This dispersion-compensating fiber comprises a core portion containing a high concentration of GeO.sub.2 and a cladding portion formed around the outer periphery of the core portion. The cladding portion comprises a first cladding containing fluorine or the like as an index reducer, a second cladding having a higher refractive index than that of the first cladding, and a third cladding which becomes a glass region substantially noncontributory to propagation of signal light. In particular, the third cladding contains a desired impurity such that the glass viscosity thereof becomes lower than that of the second cladding or pure silica cladding at a predetermined temperature.
Abstract:
High-silica glasses are formed by sintering a dried gel at temperatures below the liquidus. The gel may be formed by mixing colloidal silica particles or silica-containing liquids with appropriate liquids. Fragmentation of the gel during drying is advantageously avoided by redispersing the dried gel or sol in a liquid to yield a colloidal suspension which is then gelled, dried, and finally sintered below the liquidus.
Abstract:
The present invention relates to an optical fiber for an optical amplifier and a method for manufacturing the same, which can be applied to an optical transmission system in the S-band area (4130 nm-1530 nm). According to the present invention, silica is used as a base material and the optical fiber for an optical amplifier contains Tm3+ ions and metal ions in a first core layer formed on an inner surface of a second core layer using the MCVD (Modified Chemical Vapor Deposition) method and a solution doping method whereby the practicability and productivity of the optical fiber are remarkably improved.
Abstract:
PURPOSE: Provided is a process for producing a metal dopped silica glass, which is improved in optical property of optical fiber and prevents cracks from taking place by dopping uniformly metal particles such as germanium in the silica glass. CONSTITUTION: The process comprises the steps of: i) hydrolyzing a metal alkoxide; ii) mixing deionized water and more fumed silica than the metal alkoxide to be in a molar ratio of 1:0.1 or less; iii) mixing the hydrolyzed metal alkoxide with the mixture to form sol; iv) injecting the sol into the mold to gel; v) demolding the gel and drying it; and then vi) sintering the dried gel to vitrificate.
Abstract:
Disclosed is an optical fiber having a silica-based core and a silica-based cladding, the core comprising germania, and oxides of an alkali metal and phosphorous. By appropriately selecting the concentration of alkali metal and phosphorous oxides, fibers exhibiting low attenuation and low hydrogen aged attenuation may be obtained. In a preferred embodiment, the alkali metal oxide is potassium oxide (K 2 O).
Abstract:
Disclosed is an optical fiber having a core with an alkali metal oxide dopant in an peak amount greater than about 0.002 wt. % and less than about 0.1 wt. %. The alkali metal oxide concentration varies with a radius of the optical fiber. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained. Also disclosed are several methods of making the optical fiber including the steps of forming an alkali metal oxide-doped rod, and adding additional glass to form a draw perform. Preferably, the draw preform has a final outer dimension (d2), wherein an outer dimension (dl) of the rod is less than or equal to 0.06 times the final outer dimension (d2). In a preferred embodiment, the alkali metal oxide-doped rod is inserted into the centerline hole of a preform to form an assembly.
Abstract:
Disclosed are optical resonators having low OH content in at least the near-surface region and a process for making low OH glass article by chlorine treatment of consolidated glass of the article. Cl2 gas was used to remove OH from depth as deep as 350 m from the surface of the consolidated glass. The process can be used for treating flame-polished preformed optical resonator disks. A new process involving hot pressing or thermal reflowing for making planar optical resonator disks without the use of flame polishing is also disclosed.
Abstract:
The present invention provides an optical fiber providing high photosensitivity in the absence of hydrogen loading as well as a low numerical aperture. One aspect of the present invention relates to an optical fiber including a core, the core comprising silica doped with at least about 6 mol% germania and at least about 0.9 wt% fluorine; and a cladding surrounding the core. The optical fiber of the present invention is suitable for the production of fiber Bragg gratings.