Abstract:
Methods for forming optical fiber preforms are disclosed. According to one embodiment, a method for forming an optical fiber preform includes forming a preform core portion from silica-based glass soot. The silica-based glass soot may include at least one dopant species for altering an index of refraction of the preform core portion. A selective diffusion layer of silica-based glass soot may be formed around the preform core portion to form a soot preform. The selective diffusion layer may have an as-formed density greater than the density of the preform core portion. A diffusing species may be diffused through the selective diffusion layer into the preform core portion. The soot preform may be sintered such that the selective diffusion layer has a barrier density which is greater than the as-formed density and the selective diffusion layer prevents diffusion of the at least one dopant species through the selective diffusion layer.
Abstract:
What is disclosed includes OD-doped synthetic silica glass capable of being used in optical elements for use in lithography below about 300 nm. OD-doped synthetic silica glass was found to have significantly lower polarization-induced birefringence value than non-OD-doped silica glass with comparable concentration of OH. Also disclosed are processes for making OD-dopes synthetic silica glasses, optical member comprising such glasses, and lithographic systems comprising such optical member. The glass is particularly suitable for immersion lithographic systems due to the exceptionally low polarization-induced birefringence values at about 193 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 n c , a numerical aperture NA c . A concentration of defect color centers in the core portion is less than 1x10 16 /cm 3 . 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 n 1 , wherein the index of refraction n 1 of the first cladding portion is less than the index of refraction n c of the core portion. Methods of forming the photodarkening resistant optical fiber lasing media are also disclosed.
Abstract:
An optical fiber with large effective area, low bending loss and low attenuation. The optical fiber includes a core, an inner cladding region, and an outer cladding region. The core region includes a spatially uniform updopant to minimize low Rayleigh scattering and a relative refractive index and radius configured to provide large effective area. The inner cladding region features a large trench volume to minimize bending loss. The core may be doped with Cl and the inner cladding region may be doped with F.
Abstract:
The invention relates to a method for preparing doped oxide material, in which method substantially all the reactants (B, D) 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 (P). According to the invention, said reactants (B, D) in vaporous and reduced form are mixed together to a gas flow (BD) of reactants, which gas flow (BD) is further condensated fast in such a manner that substantially all the component parts of the reactants (B, D) reach a supersaturated state substantially simultaneously by forming oxide particles (P) in such a manner that there is no time to reach chemical phase balances.
Abstract:
Preparation of halogen-doped silica is described. The preparation includes doping silica with high halogen concentration and sintering halogen-doped silica to a closed-pore state. The sintering includes a high pressure sintering treatment and a low pressure sintering treatment. The high pressure sintering treatment is conducted in the presence of a high partial pressure of a gas-phase halogen doping precursor and densifies a silica soot body to a partially consolidated state. The low pressure sintering treatment is conducted in the presence of a low partial pressure of gas-phase halogen doping precursor and transforms a partially consolidated silica body to a closed-pore state. The product halogen-doped silica glass exhibits little foaming when heated to form fibers in a draw process or core canes in a redraw process.
Abstract:
One embodiment of the disclosure relates to a method of making an optical fiber comprising the steps of: (i) exposing a silica based preform with at least one porous glass region having soot density of r to a gas mixture comprising SiCl 4 having SiCl 4 mole fraction y SiCl4 (preferably of less than 0.03) at a doping temperature T dop such that parameter X is larger than 0.03 to form the chlorine treated preform, wherein X is defined as a function of density r, doping temperature T dop , SiCl4 mole fraction y SiCl4 , and the density p s of the fully densified soot layer; and (ii) exposing the chlorine treated preform to temperatures above 1400 °C to completely sinter the preform to produce sintered optical fiber preform with a chlorine doped region; and (iii) drawing an optical fiber from the sintered optical preform.