Abstract: One embodiment of the present disclosure relates to an optical fiber having lower transmission loss. The optical fiber is an optical fiber comprised of silica-based glass and includes a core including a central axis and a cladding. The cladding surrounds the core and has a refractive index lower than a refractive index of the core. The core contains phosphorus, chlorine, and fluorine. The core further includes an alkali metal element or an alkaline earth metal element. In a cross section of the optical fiber orthogonal to the central axis, a ratio Rp/Ra of a radius Rp of a phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more.

Abstract: A supercontinuum source, comprises a pump source and a supercontinuum generator configured for receiving electromagnetic radiation derived from the pump source and for generating supercontinuum radiation, the supercontinuum generator comprising a nonlinear microstructured optical fibre having a core region comprising silica. The core region includes a dopant selected to reduce light-induced non-bridging oxygen hole centre loss in the nonlinear microstructured optical fibre.

Abstract: An apparatus for optical fiber manufacturing process is provided, including a raw material providing structure, a dopant providing structure, and a preform forming substrate tube. The dopant providing structure is disposed at a downstream side of the raw material providing structure and in communication with the raw material providing structure. The dopant providing structure includes an outer tube, a first inner tube, a first dopant providing container, a second inner tube, and a second dopant providing container. The first inner tube is disposed in the outer tube. The first dopant providing container is disposed in the first inner tube. The second inner tube is disposed in the outer tube at a downstream of the first inner tube. The second dopant providing container is disposed in the second inner tube. The preform forming substrate tube is disposed at a downstream side of the dopant providing structure.

Abstract: Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

Abstract: A functionalized fiber. The functionalized fiber includes a fiber strand and silica nanoparticles at least partially encapsulating the fiber strand. The silica nanoparticles are synthesized by hydrolyzing a tetramethyl orthosilicate in hydrochloric acid to form silicic acid monomers. The silicic acid monomers are diluted in acetone and irradiated for a time that is less than 90 seconds with an energy source configured to generate microwave frequency energy to polymerize the silicic acid monomers into the silica nanoparticles.

Abstract: The present disclosure provides optical fiber preforms formed from core canes having large core-clad ratio, intermediate core-cladding assemblies, and methods for making the preforms and core cladding assemblies. The preforms are made from core canes having a contoured end surface. The contoured end surface(s) include a depression that acts to reduce the stress that develops at the junction of the end surface of the core cane with a soot cladding monolith arising from differences in the coefficient of thermal expansions of the core can and soot cladding monolith. The contoured end surface(s) leads to preforms having low defect concentration and low probability of failure during fiber draw.

Abstract: Ultrashort pulse fiber amplifier having a pulse width from 200 ps to 200 fs comprising a rare earth oxide doped multicomponent glass fibers for laser amplification, including a core and a cladding, the core comprising at least 2 weight percent glass network modifier selected from BaO, CaO, MgO, ZnO, PbO, K2O, Na2O, Li2O, Y2O3, or combinations; wherein the mode of the core is guided with step index difference between the core and the cladding, a numerical aperture of the fiber is between 0.01 and 0.04; core diameter is from 25 to 120 micron, and a length of the gain fiber is shorter than 60 cm.

Abstract: Rare earth oxides doped multicomponent glass fibers for laser generation and amplification, including a core and a cladding, the core comprising at least 2 weight percent glass network modifier selected from BaO, CaO, MgO, ZnO, PbO, K2O, Na2O, Li2O, Y2O3, or combinations; wherein the mode of the core is guided with step index difference between the core and the cladding, a numerical aperture of the fiber is between 0.01 and 0.04; core diameter is from 60 to 150 micron, and a length of the gain fiber is shorter than 60 cm.

Abstract: Rare earth oxides doped multicomponent glass fibers for laser generation and amplification, including a core and a cladding, the core comprising at least 2 weight percent glass network modifier selected from BaO, CaO, MgO, ZnO, PbO, K2O, Na2O, Li2O, Y2O3, or combinations; wherein the mode of the core is guided with step index difference between the core and the cladding, a numerical aperture of the fiber is between 0.01 and 0.04; core diameter is from 25 to 120 micron, and a length of the gain fiber is shorter than 60 cm.

Abstract: A method includes (1) a thermal diffusion process for using an alkali metal salt raw material having an average particle size of 1 mm or less in diameter, supplying a vapor of the alkali metal salt produced by heating the alkali metal salt raw material together with a carrier gas to the inside of a silica-based glass pipe from one end side of the glass pipe, and heating the glass pipe using a heat source which relatively moves in a longitudinal direction of the glass pipe to cause an oxidation reaction of an alkali metal and thermally diffuse the alkali metal into an inner side of the glass pipe, (2) a collapsing process for collapsing the glass pipe after the thermal diffusion process to prepare a core rod; and (3) a cladding portion addition process for adding a cladding portion around the core rod prepared in the collapsing process.

Abstract: A fiber block is configured with a fiber block including a Nd-doped active fiber and a pump-light delivery fiber which has a stretch extending along the active fiber in a side-to-side configuration so as to lunch pump light into the Nd-doped core of the active fiber. The core of the active fiber is surrounded by at least one or more claddings which, like the core, have a double bottleneck cross-section with a relatively large-area central region and relatively small input and output regions. The pump light delivery fiber is structured to have a substantially dumbbell cross-section with a relatively small-area central region coextending with the central region of the active fibers. The active fiber is dimensioned so that the overall length of the active fiber is configured to provide for the maximal amplification of the laser signal in a 900 nm range while limiting amplification in the 1060 nm range to the preset threshold.

Abstract: An IR supercontinuum source for generating supercontinuum in the MIR or possibly LWIR spectral bands comprises a supercontinuum fiber formed from a heavy metal oxide host glass having low optical loss and high non-linearity over the spectral band that is stable, strong and chemically durable. The supercontinuum fiber is suitably a depressed inner clad fiber configured to support only single transverse spatial mode propagation of the pump signal and supercontinuum. The source suitably includes a tapered depressed inner clad fiber to couple the pump signal into the supercontinuum fiber. The source may be configured as an “all-fiber” source.

Abstract: A tellurium oxide glass that is stable, strong and chemically durable exhibits low optical loss from the UV band well into the MIR band. Unwanted absorption mechanisms in the MIR band are removed or reduced so that the glass formulation exhibits optical performance as close as possible to the theoretical limit of a tellurium oxide glass. The glass formulation only includes glass constituents that provide the intermediate, modifiers and any halides (for OH— reduction) whose inherent absorption wavelength is longer than that of Tellurium (IV) oxide. The glass formulation is substantially free of Sodium Oxide and any other passive glass constituent including hydroxyl whose inherent absorption wavelength is shorter than that of Tellurium (IV) oxide. The glass formulation preferably includes only a small residual amount of halide.

Abstract: [Object] In manufacturing a GRIN lens by a sol-gel method, an operation for preparing a wet gel is facilitated and cracking in a base material during sintering and foaming during drawing are prevented. [Solution] The object is achieved by obtaining a GRIN lens by producing a wet gel from an alcohol solution containing a silicon alkoxide, a dopant alkoxide, and a boron alkoxide as the main ingredients, leaching the same, drying the same to form a dry gel, and sintering and drawing the same.

Abstract: A method of producing a conversion element includes forming a preform from a glass, reshaping the preform into a structured glass fiber using a structuring element, and dividing the glass fiber into conversion elements.

Abstract: The present invention is generally directed to a method of making chalcogenide glasses including holding the melt in a vertical furnace to promote homogenization and mixing; slow cooling the melt at less than 10° C. per minute; and sequentially quenching the melt from the top down in a controlled manner. Additionally, the present invention provides for the materials produced by such method. The present invention is also directed to a process for removing oxygen and hydrogen impurities from chalcogenide glass components using dynamic distillation.

Abstract: The present invention provides a method of making rare earth (RE) doped optical fiber using BaO as co-dopant instead of Al or P commonly used for incorporation of the RE in silica glass by MCVD and solution doping technique. The method comprises deposition of particulate layer of GeO2 doped SiO2 with or without small P2O5 for formation of the core and solution doping by soaking the porous soot layer into an aqueous solution of RE and Ba containing salt. This is followed by dehydration and sintering of the soaked deposit, collapsing at a high temperature to produce the preform and drawing of fibers of appropriate dimension. The use of Ba-oxide enables to eliminate unwanted core-clad interface defect which is common in case of Al doped fibers. The fibers also show good RE uniformity, relatively low optical loss in the 0.6-1.6 ?m wavelength region and good optical properties suitable for their application in amplifiers, fiber lasers and sensor devices.

Abstract: An optical fiber apparatus is suitable to operate under irradiation, more particularly to mitigating the damage of a rare-earth-doped optical fiber element as part of an optical fiber assembly causes by irradiation. The irradiation mitigation attributes to a photo-annealing apparatus including at least a shorter wavelength photo-annealing spectral content, which is relative to that of a pump light source, for effectively photo-annealing the rare-earth-doped fiber element. Photo-annealing by such shorter wavelength light results in a fast and nearly complete recovery of radiation induced attenuation of the rare-earth-doped optical fiber element in the wavelength range from 900 nm to 1700 nm.

Abstract: Photodarkening resistant optical fiber lasing media and fiber lasers incorporating the same are disclosed. In one embodiment, an optical fiber lasing medium includes a core portion formed from silica-based glass comprising a rare-earth dopant and deuterium, the core portion having an index of refraction nc, a numerical aperture NAc. A concentration of defect color centers in the core portion is less than 1×1016/cm3. Deuterium is combined with the defect color centers to form reacted defect color centers that do not absorb ultraviolet and visible wavelengths of light. A first cladding portion is formed from silica-based glass, the first cladding portion surrounding and directly contacting the core portion and having an index of refraction n1, wherein the index of refraction n1 of the first cladding portion is less than the index of refraction nc of the core portion. Methods of forming the photodarkening resistant optical fiber lasing media are also disclosed.

Abstract: A radiation-resistant optical fiber includes at least one core and at least one first cladding surrounding the core. The core includes a phosphosilicate matrix, the core being rare-earth doped, the rare earth being chosen from erbium, ytterbium, neodymium, thulium or erbium-ytterbium of thulium-holmium codoped and the core is cerium codoped. Also described is a method for radiation-hardening an optical fiber including the core having a phosphosilicate matrix, the core being rare-earth doped, the rare earth being chosen from erbium, ytterbium, neodymium and thulium, or erbium-ytterbium or thulium-holmium codoped, and including a step of cerium codoping the core of the fiber.

Abstract: Disclosed is a method of fabricating an optical fiber or an optical device doped with reduced metal ion and/or rare earth ion, comprising steps of: forming a partially-sintered fine structure in a base material for fabricating the optical fiber or the optical device; soaking the fine structure into a doping solution containing a reducing agent together with metal ion and rare earth ion during a selected time; drying the fine structure in which the metal ion and/or rare ion are/is soaked; and heating the fine structure such that the fine structure is sintered.

Abstract: A method of manufacturing a photonic band gap fiber base material includes: a forming step of continuously forming a columnar core glass body 10 and a clad glass body 20 which coats the core glass body to obtain an intermediate base material 110; a hole making step of making holes 30 in the clad glass body 20; an insertion step of inserting in the holes 30 a plurality of bilayer glass rods 40 in which an outer layer 42 which has the same refractive index as the clad glass body coats high refractive index portions 41 having a higher refractive index than a refractive index of the clad glass body 20; and a heating step of heating the intermediate base material 110 and integrating the intermediate base material 110 and the bilayer glass rods 40.

Abstract: A method of manufacturing a photonic band gap fiber base material includes: a forming step of continuously forming a columnar core glass body 10 and a clad glass body 20 which coats the core glass body to obtain an intermediate base material 110; a hole making step of making holes 30 in the clad glass body 20; an insertion step of inserting in the holes 30 a plurality of bilayer glass rods 40 in which an outer layer 42 which has the same refractive index as the clad glass body coats high refractive index portions 41 having a higher refractive index than a refractive index of the clad glass body 20; and a heating step of heating the intermediate base material 110 and integrating the intermediate base material 110 and the bilayer glass rods 40.

Abstract: A glass preform manufacturing method includes: generating glass fine particles by hydrolyzing a source gas in an oxyhydrogen flame; depositing the generated glass fine particles to form a torous glass preform; immersing the porous glass preform in an additive solution including an additive solvent in which a compound containing a desired additive is dissolved to impregnate the additive solution into the porous glass preform; first replacing of replacing the additive solvent remaining in the porous glass preform with the replacement solvent by immersing the porous glass preform in which the additive solution remains in a replacement solvent in which a solubility of the additive is lower than that in the additive solvent and having miscibility with the additive solvent; drying the porous glass preform after the first replacing; and sintering the dried porous glass preform to transparently vitrify the dried porous glass preform.

Abstract: A twin fiber laser arrangement is configured with active and passive fibers supporting respective signal and pump lights and a reflective coating surrounding the fibers along a section of the arrangement. The passive fiber has regions covered by respective protective layer and coating-free regions alternating with the layer covered regions, wherein the reflective coating is configured to overlap the protective layer which shields the end of the reflective coating from high power pump light.

Abstract: An isothermal, low pressure-based process of depositing material within a substrate has been developed and results in creating an extremely narrow reaction zone within which a more uniform and efficient deposition will occur. Sets of isothermal plasma operating conditions have been found that create a narrow deposition zone, assuring that the deposited material is clear glass rather than soot particles. The chemical delivery system, in one arrangement, utilizes rods of solid phase source material (which may otherwise be difficult to obtain in gaseous form). The operating conditions are selected such that the hot plasma does not transfer a substantial amount of heat to the substrate tube, where the presence of such heat has been found to result in vaporizing the reactant material (creating soot) and developing hot spots.

Abstract: Optical fiber preforms can comprise a glass preform structure with an inner cavity. A powder can be placed within the inner cavity having an average primary particle size of less than about one micron. The powder can be in the form of an unagglomerated particles or a powder coating with a degree of agglomeration or hard fusing ranging from none to significant amounts as long as the primary particles are visible in a micrograph. Powders can be placed within a preform structure by forming a slurry with a dispersion of submicron/nanoscale particles within a cavity within the preform. In other embodiments, a powder coating is formed within a preform structure by depositing the powder coating directly from a reaction product stream. The formation of the powder coating can be formed within the reaction chamber or outside of the reaction chamber by flowing the product particle stream through a conduit leading to the preform structure. In additional embodiments, a powder coating is placed on an insert, e.g.

Abstract: A polymer-based optical waveguide amplifier comprises a polymer host material doped with rare earth ions wherein the polymer host material is a material that functions as a resist in a direct patterning technique. The polymer host material can be epoxy novalac resin doped with Er3+ ions and Yb3+ ions, and the direct patterning comprises electron beam direct writing or UV printing.

Abstract: A resonant enhanced photosensitive material includes a trap center that is adapted to interact with light and enhances the photosensitivity of the material based on a resonant interaction process with photons. The invention provides enhanced photosensitivity materials and, especially a method for enhancing photosensitivity in glasses, glass ceramics and ceramics.

Abstract: The invention relates to a method for the economic production of a blank for a component made from laser-active quartz glass in any form or dimension. The method comprises the following method steps: a) preparation of a dispersion with a solids content of at least 40 wt. %, comprising SiO2 nanopowder and doping agents, including a cation of the rare earth metals and transition metals in a fluid, b) granulation by agitation of the dispersion, with removal of moisture to form a doped SiO2 granulate of spherical porous granular particles with a moisture content of less than 35 wt. % and a density of at least 0.95 g/cm3, c) drying and purification of the SiO2 granulate, by heating to a temperature of at least 1000° C. to form doped porous SiO2 grains with an OH content of less than 10 ppm and d) sintering or fusing the doped SiO2 grains in a reducing atmosphere to give the blank made from doped quartz glass.

Abstract: A method for preparing doped oxide material, in which method substantially all the reactants forming the oxide material are brought to a vaporous reduced form in the gas phase and after this to react with each other in order to form oxide particles. The reactants in vaporous and reduced form are mixed together to a gas flow of reactants, which gas flow is further condensated fast in such a manner that substantially all the component parts of the reactants reach a supersaturated state substantially simultaneously by forming oxide particles in such a manner that there is no time to reach chemical phase balances.

Abstract: A method of fabrication of a thermally stabilized Type I fiber Bragg grating-based temperature sensing device includes doping a fiber core material with germanium or germanium oxide for enhancing photosensitivity, co-doping the fiber core material with fluorine or chorine or for increasing a mean coordination number; and ultraviolet laser inscribing a periodic or quasiperiodic modulated refractive index structure in the fiber core using a laser energy operating at less than 1000 milliJoules per square centimeter per pulse. The resulting sensor is operable for more than 1000 hours at temperatures up to at least 550 degrees Celsius.

Abstract: A first step, in which P2O5-containing glass is deposited inside a silica glass pipe, and a second step, in which a Cl2-containing gas is introduced into the pipe and the P2O5-containing glass is dehydrated by heating the pipe, are repeated alternately. A third step, in which glass that does not contain P2O5 is deposited on the inside of the silica glass pipe, may further be provided such that the first step, the second step, and the third step are repeatedly performed in this order. A rare-earth-doped optical fiber, which has a attenuation of 15 dB/km or less at a wavelength of 1200 nm, comprises a core region and a cladding region enclosing the core region, wherein the core region includes phosphorus of 3 wt % or more, aluminum of 0.3 wt % or more, a rare-earth element of 500 wtppm or more, and chlorine of 0.03 wt % or more, and the cladding region has a refractive index that is lower than the refractive index of the core region.

Abstract: Various embodiments described herein include rare earth doped glass compositions that may be used in optical fiber and rods having large core sizes. Such optical fibers and rods may be employed in fiber lasers and amplifiers. The index of refraction of the glass may be substantially uniform and may be close to that of silica in some embodiments. Possible advantages to such features include reduction of formation of additional waveguides within the core, which becomes increasingly a problem with larger core sizes.

Abstract: A method of fiber core material band gap engineering for artificially modifying fiber material properties is provided. The method includes doping the fiber core material with one or more atoms for enhancing photosensitivity to the fiber material. The method also includes co-doping the fiber core material with one or more ions for enhancing an amorphous network crosslink mean coordination number. The method further includes thermally annealing the fiber core material for widening the band gap of the fiber core material.

Abstract: Provided is an optical glass comprising, denoted as molar percentages: 10 to 20 percent SiO2, 5 to 40 percent B2O3, SiO2+B2O3=15 to 50 percent, 0 to 10 percent Li2O, 12 to 36 percent ZnO, where 3×Li2O+ZnO?18 percent, 5 to 30 percent La2O3, 0 to 20 percent Gd2O3, 0 to 10 percent Y2O3, La2O3+Gd2O3=10 to 30 percent, La2O3/SIGMA(?)RE2O3=0.67 to 0.95 (where SIGMA(?)RE2O3=La2O3+Gd2O3+Y2O3+Yb2O3+Sc2O3+Lu2O3), 0.5 to 10 percent ZrO2, 1 to 15 percent Ta2O5, 1 to 20 percent WO3, Ta2O5/WO3?2.5 (molar ratio), 0 to 8 percent Nb2O5, 0 to 8 percent TiO2; and having a refractive index nd of not less than 1.87 and an Abbé number nu(v)d of not less than 35 but less then 40. A method for manufacturing a preform for precision press molding by separating a glass melt gob from a glass melt obtained by mixing, heating, and melting glass starting materials, and forming a preform in a glass melt gob cooling step, said mixing, heating, and melting of glass starting materials is conducted so as to obtain the above optical glass.

Abstract: Provided is an optical glass having high-refractivity low-dispersion properties, having a low glass transition temperature and having the property of being softened at a low temperature so that a preform therefrom is precision press-moldable, and the optical glass comprises, as essential components, B2O3, La2O3, Gd2O3 and ZnO and has a refractive index (nd) of over 1.86, an Abbe's number (vd) of less than 35 and a glass transition temperature (Tg) of 630° C. or lower.

Abstract: A Raman amplification active optical fiber comprises a core containing silica oxide (SiO2), lithium oxide (Li2O), germanium oxide (GeO2), and barium oxide (BaO). The core contains 30 to 90 molar percent of SiO2 and less than 50 molar percent of the combination of LiO2, GeO2, and BaO. Application of the fiber to a multiwavelength Raman fiber laser.

Abstract: A method for forming an optical waveguide is disclosed. The method comprises first forming a lower cladding layer having at least one waveguide support. Next, a core material is formed onto the waveguide support using a high density plasma chemical vapor deposition (HDPCVD) process. Finally, an upper cladding layer is formed over the core material, such that the upper cladding layer and the lower cladding layer surround the core material.

Abstract: A device amplifies light at wavelengths in the vicinity of 1420-1530 nm, using thulium doped silica-based optical fiber. This wavelength band is of interest as it falls in the low-loss optical fiber telecommunications window, and is somewhat shorter in wavelength than the currently standard erbium doped silica fiber amplifier. The device thus extends the band of wavelengths which can be supported for long-distance telecommunications. The additional wavelength band allows the data transmission rate to be substantially increased via wavelength division multiplexing (WDM), with minimal modification to the standard equipment currently used for WDM systems. The host glass is directly compatible with standard silica-based telecommunications fiber. The invention also enables modified silicate based amplifiers and lasers on a variety of alternative transitions. Specifically, an S-band thulium doped fiber amplifier (TDFA) using a true silicate fiber host is described.

Abstract: The optical amplifier has a waveguide including a core and a cladding. The cladding at least partially surrounds the core and is doped with at least one species of rare earth ion in the range of 5 to 75 wt %. In another embodiment, the core is doped with Er3+ in the range of 7 to 9 wt % and with Yb3+ in the range of 11 to 13 wt %.

Abstract: A method for forming a multicore fiber laser array includes inserting a plurality of rare-earth doped rods into a corresponding plurality of hollow capillaries, and arranging the resulting plurality of filled capillaries into a preform pattern. The plurality of filled capillaries are collapsed into an initial preform structure, wherein a portion of the material of the capillaries forms an initial inner cladding. The initial preform structure is inserted into a cylinder, wherein the cylinder and the initial preform structure are fused so as to form a final preform structure with a final inner cladding having an increased thickness with respect to the initial inner cladding. At least one flat surface is formed along the length of the final preform structure, and a fiber is simultaneously drawn from the final preform structure and a layer of outer cladding material.

Abstract: An optical amplifier including: an erbium-doped amplifier medium, a first excitation generator and a second excitation generator. The first excitation generator is adopted to cause a first type excitation of the at least one kind of rare-earth ions to cause a population inversion between the laser upper level and the laser lower level. The second excitation generator is adopted to cause a second type excitation of the at least one kind of rare-earth ions from the excited state absorption lower level to a high excited level which is equal to or higher than the laser upper level.

Abstract: A hybrid method of and apparatus for producing a structure capable of being drawn into an optical fiber. The method includes the steps of conducting vapor-phase reactants into an interior region of a glass tube, conducting aerosol form reactants into the interior of the glass tube. The tube is exposed to a heat, thereby causing a reaction among the vapor-phase and aerosol reactants. The reaction yields a product, in a solid form, within the tube. The apparatus includes a reaction tube, a vapor-phase reactant conduit, an aerosol-form conduit, and a heat source. The vapor-phase and aerosol-form reactant conduits facilitate introduction of vapor-phase and aerosol-form reactants into the reaction tube. The aerosol-form reactants are introduced proximate to a reaction zone created by the heat source. The aerosol-form reactants conduit and heat source travel the axial length of the reaction tube.

Abstract: Disclosed is an optical fiber article for receiving pump radiation of a first wavelength for amplifying or generating radiation of a second wavelength. The optical fiber article includes a core for propagating light of the second wavelength. The core has a first index of refraction and includes a rare earth material. A cladding surrounds the core and has a second index of refraction that is less than the first index of refraction. The outer circumference of the cladding can include a plurality of sections, where the plurality of sections includes at least one substantially straight section and one inwardly curved section. The optical fiber article can also include at least one outer layer surrounding the cladding, where the index of refraction of the outer layer is less than the second refractive index. Methods for producing the optical fiber article are also disclosed, as well as methods for providing a preform for drawing such an optical fiber article.

Abstract: Techniques are described for fabricating a preform from a soot body. In one described technique, a soot body is loaded into a substrate tube, and the position of the soot body is stabilized within the tube. The tube is then rotated around its longitudinal axis. Heat is applied from a heat source to the substrate tube at a first end of the soot body to cause the first end of the soot body to begin to sinter and to cause the substrate tube to begin to at least partially collapse around the sintered portion of the soot body. The heat source is then advanced along the substrate tube and the soot body to cause a progressive sintering of the soot body, and to cause a progressive, at least partial, collapse of the substrate tube around the sintered portion of the soot body.

Abstract: A high-gain phosphate glass composition, which can be used to produce ultra-short gain length lasers and optical amplifiers is described wherein the composition of the glass in addition to exhibiting high gain for lasers and amplifiers, also exhibits high thermal shock resistance, high cross section, insignificant concentration quenching, and high solubility for rare earth ions and other properties which enable the material to be fabricated into a new class of ultra-short length micro-laser, fiber laser and amplifier configurations and designs.

Abstract: The present invention discloses a process for making rare earth (RE) doped optical fiber by using RE oxide coated silica nanoparticles as the precursor material, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc.

Abstract: The present invention provides a method of fabricating rare earth doped preforms and optical fibers by a combination of modified chemical vapor deposition (MCVD) process and solution doping technique said MCVD process is used to develop matched or depressed clad structure inside a silica glass substrate tube followed by deposition of porous silica soot layer containing GeO2, P2O5 or such refractive index modifiers by the backward deposition method for formation of the core and presintering the deposited particulate layer by backward pass with flow of GeCl4 and/or corresponding dopant halides, soaking the porous soot layer into an alcoholic/aqueous solution of RE-salts containing codopants such as AlCl3 in definite proportion, drying, oxidation, dehydration and sintering of the RE containing porous deposit and by collapsing at a high temperature to produce the preform followed by drawing the fibers by known technique to produce fibers with suitable core-clad dimensions and geometry.

Abstract: The specification describes the production of optical fibers and optical fiber preforms using Chemical Powder Deposition (CPD). In this process a slurry of silica powders and dopant powders in a liquid carrier is prepared and the inside surface of a silica glass starter tube is coated with the slurry, then dried. The coating is then consolidated and the tube collapsed as in the conventional MCVD process. Multiple coatings, and coatings with varying compositions, can be used to produce any desired profile. In an alternative embodiment, doped silica glass of the desired final composition is prepared, and then pulverized to form the powder for the slurry. In both embodiments, the use of powders of known composition in the slurry allows direct control over the final glass composition, as compared with conventional processes in which the composition in the final glass is indirectly controlled by control of the thermodynamics of a vapor phase reaction.