Abstract: The present invention provides a method for inducing a refractive index change in a lead silicate glass material comprising: providing a lead silicate glass material; and irradiating the lead silicate glass material to increase the index of refraction of said lead silicate glass material. The present invention also provides a photo-induced lead silicate glass grating.

Abstract: Glasses of the present invention are tellurite and oxyhalide glasses doped with rare-earth ion, which can be applied to highly efficient optical amplifiers and lasers for optical communication. They are thermally and chemically stable during and after the fabrication processes of the optical fiber. The glass material includes 20˜70 mole % of TeO2, a heavy metal oxide, 0.001˜10 mole % of a rare earth ion dopant, 5˜30 mole % of MO, M being selected from a group consisting of Mg, Ca, Sr, Ba, Zn and Pb, and optionally 1˜20 mole % of R2O, R being selected from a group consisting of Li, Na, K, Rb and Cs. In the composition of the glass, 3˜18 mole % of MO and R2O may be substituted by the metal halides. The glasses of the present invention are similar in phonon energy to the conventional tellurite glasses not to increase the non-radiative transition rate. Further, the fluorescence lifetime is additionally increased in case of partial substitution of oxide to halide.

Abstract: A glass consisting essentially of antimony oxide. An optically active glass consisting essentially of antimony oxide and up to about 4 mole % of an oxide of a rare earth element. A rare earth-doped, antimony oxide-containing glass including 0-99 mole % SiO2, 0-99 mole % GeO2, 0-75 mole % (Al, Ga)2O3, 0.5-99 mole % Sb2O3, and up to about 4 mole % of an oxide of a rare earth element. The oxide of the rare earth element may comprise Er2O3. The glass of the invention further includes fluorine, expressed as a metal fluoride. An optical energy-producing or light-amplifying device, in particular, an optical amplifier, comprising the above-described glass. The optical amplifier can be either a fiber amplifier or a planar amplifier, either of which may have a hybrid composition. Embodiments of the glass of the invention can be formed by conventional glass making techniques, while some of the high content antimony oxide embodiments are formed by splat or roller quenching.

Abstract: A process of manufacturing a silica glass article comprising the steps of: (1) irradiating a silica glass article with electromagnetic waves to generate defects therein; and (2) immersing the thus irradiated silica glass article in an atmosphere comprising a hydrogen gas, thereby providing the resulting silica glass article with a characteristic that is effective for preventing it substantially from increasing its absorption within an ultraviolet region due to ultraviolet ray irradiation. Also disclosed are a silica glass article or a glass fiber produced according to the manufacturing process.

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: There is disclosed second-order nonlinear glass material wherein a part having second-order nonlinearity contain Ge, H and OH and second-order nonlinear optical constant d of 1 pm/V or more, and a method for producing second-order nonliner glass material comprising treating a porous class material containing Ge with hydrohen, sintering it and subjecting it to a ultraviolet poling treatment. There can be provided second-order nonlinger glass material having second-order nonlinearity which is a sufficiently high and has a sufficiently long lifetime for a practical purpose, in use of the glass material for optical elements or the like.

Abstract: Alkali tungstate, molybdate and vanadate glasses, and telecommunications components embodying such glasses, the compositions of the glasses consisting essentially of 15-70 mol percent of at least one oxide selected from the group consisting of WO3, MoO3 and VO2.5, 0-35% CrO3, 0-15% UO3, the total WO3 plus MoO3 plus VO2.5 plus CrO3 plus UO3 being 50-70%, 20-50% R2O where R represents at least two elements selected from the group consisting of Li, Na, K, Rb, Cs, Ag and T1, and optionally containing 0-10% MO where M is selected from the groups of elements consisting of Ca, Ba, Sr, Mg, Cd, Pb, 0-5 % X2O3 where x is at least one element selected from the group consisting of Al, Ga, In and Bi, 0-5% of at least one transition metal oxide, 0-15% P2O5 and/or TeO2 and 0-5% of a rare earth oxide selected from the lanthanide series.

Abstract: A family of alkali-tungsten-tellurite glasses that consist essentially of, as calculated in mole percent, 10-90% TeO2, at least 5% W03 and at least 0.5% R2O where R is Li, Na, K, Cs, Tl and mixtures, that may contain a lanthanide oxide as a dopant, in particular erbium oxide, and that, when so doped, is characterized by a fluorescent emission spectrum having a relatively broad FWHM value.

Abstract: An optical fiber used for an optical amplifier, is formed by doping glass with rare-earth ions. Both praseodymium ions (Pr+3) and erbium ions (Er+3) are used as the rare-earth ions, and the glass is a fluoride glass or a sulfide glass. The optical fiber can be used at wavelengths of both 1.3 &mgr;m and 1.55 &mgr;m. The light amplification efficiency of an optical amplifier made of the optical fiber can be improved compared to that of an optical amplifier formed of only Pr+3 or only Er+3.

Abstract: A family of fluorotellurite glasses, the composition of which consist essentially of, as calculated in mole percent, 30-75% TeO2, 15-60% ZnF2 and 0.005-10% of an oxide of erbium, thulium or holmium, and amplifying optical components produced from these glasses.

Abstract: A process of manufacturing a silica glass article comprising the steps of: (1) irradiating a silica glass article with electromagnetic waves to generate defects therein; and (2) immersing the thus irradiated silica glass article in an atmosphere comprising a hydrogen gas, thereby providing the resulting silica glass article with a characteristic that is effective for preventing it substantially from increasing its absorption within an ultraviolet region due to ultraviolet ray irradiation. Also disclosed are a silica glass article or a glass fiber produced according to the manufacturing process.

Abstract: A gain medium for use in optical amplifiers or laser oscillators is disclosed. The gain medium includes a transition-metal doped glass-ceramic material having a crystal phase and a glass phase. The crystal phase is formed in situ in the glass phase, with the transition metal ions preferentially partitioning into the crystals from the glass phase. The crystals so formed have a size of less than 50 nm, and the transition metal ions within them are capable of lasing at a wavelength within the range of about 900 to 3000 nm. Also disclosed are amplifier and laser oscillator configurations, where the glass-ceramic gain medium is applied in a variety of configurations. Also disclosed is a method of amplifying a signal of light wherein the glass-ceramic gain medium is pumped with light energy so as to excite the transition metal ions, and the signal of light is transmitted through the gain medium while the transition metal ions are excited, whereby the signal of light is amplified.

Abstract: Devices are made comprising a tin-phosphorous oxyfluoride glass, which has been exposed to light, preferably shorter in wavelength than the absorption edge of the glass, to change the refractive index change of the glass. The glasses can be used to form planar and fiber devices, including core/clad structures for guiding light.

Abstract: An optical fiber for use in a light amplifier. The optical fiber is formed by doping a gerrnanium-gallium-sulfur (Ge—Ga—S) glass containing less sulfur than a GeS2—Ga2S3 stoichiometric composition line with a rare earth element, and further contains 0.1˜10 atomic % of a halogen element base on the Ge—Ga—S glass. By using optical fiber, clustering of praseodymium (Pr+3) ions can be suppressed even when the concentration of added Pr+3 is high, thereby improving light amplification efficiency.

Abstract: A low-dielectric-constant glass fiber having a glass composition comprising, by % by weight, 45 to 60% of SiO2, 8 to 20% of Al2O3, 15 to 30% of B2O3, 0 to 5% of MgO, 5%, exclusive of 5%, to 12% of CaO, 0 to 1.0% of Li2O+Na2O+K2O, 0.5 to 5% of TiO2 and 0 to 2% of F2 is suitable for use for reinforcing a high-density printed wiring board required to have a low dielectric tangent and its peripheral members.

Abstract: The present invention relates to a molding composition based on sinterable materials, comprising

Abstract: The present invention is directed to a fluorinated rare earth doped glass composition and method for making a glass-ceramic optical article therefrom, e.g. optical fiber waveguides, fiber lasers and active fiber amplifiers, having application in the 1300 nm and 1550 nm telecommunications windows. The inventive compositions include Pr3+ and/or Dy3+ in a concentration range of between 300-2,000 ppmw and Ag+ in a concentration range of between 500-2,000 ppmw; or Er3+ in a concentration range of between 500-5,000 ppmw and Ag+ in a concentration range of between 0-2,000 ppmw. The monovalent silver ion provides an ionic charge balanced glass-ceramic crystal. These compositions exhibit reduced or absent rare earth ion clustering and fluorescence quenching effects in the presence of high concentrations of rare earth ion dopants.

Abstract: A family of alkali-tungsten-tellurite glasses that consist essentially of, as calculated in mole percent, 10-90% TeO2, at least 5% WO3 and at least 0.5% R2O where R is Li, Na, K, Cs, Tl and mixtures, that may contain a lanthanide oxide as a dopant, in particular erbium oxide, and that, when so doped, is characterized by a fluorescent emission spectrum having a relatively broad FWHM value.

Abstract: This ultralow-loss glass is characterized in that high purity silica glass contains 1 to 500 wt.ppm of at least one network modifying oxide. It is assumed that the network modifying oxide appropriately loosens the tetrahedral network structure of silica and hence Rayleigh scattering is decreased. Examples of the network modifying oxide include Na.sub.2 O, K.sub.2 O, Li.sub.2 O, MgO, CaO, and PbO. Since Rayleigh scattering losses are minimal in comparison with those of high purity silica glass, this impurity-added silica glass is excellent as a base material of a glass fiber for a long-distance transmission.

Abstract: A Ge--Ga--S-based glass composition having light amplifying characteristics and an apparatus for optical communications using the glass composition are provided. The present invention includes a sulfur-poor Ge--Ga--S based host glass which includes less S than compositions on the composition line of GeS.sub.2 --G.sub.2 S.sub.3 on the ternary phase diagram of Ge--Ga--S, and a rare earth active material doped on the host glass for luminescence and light amplification. Ga of no more than about 10 mol % is included in the host glass. Also, Pr.sup.3+ ions are used as the rare earth active material. Furthermore, for stable vitrification and a blue shift of a short wavelength absorption band, a vitrification stabilizer such as Br and I is added to the host glass.

Abstract: A Ge--Ga--S-based glass composition for performing an optical amplification and an apparatus for optical communications using the same are provided. In the glass composition according to the present invention, an active material for performing luminescence and optical amplification operations is added to the Ge--Ga--S host glass and a transition metal ion moving the distribution of optical amplification gains is added in a range from 0.01 mole % to 0.2 mol %.

Abstract: An optical article having a rare earth doped, fluorinated aluminosilicate glass core composition consisting essentially, in mole %, of:______________________________________ SiO.sub.2 0-90 GeO.sub.2 0-90 Na.sub.2 O 0-25 Li.sub.2 O 0-10 K.sub.2 O 0-25 Rb.sub.2 O 0-25 Cs.sub.2 O 0-25 Al.sub.2 O.sub.3 5-40 Ga.sub.2 O.sub.3 5-40 RE.sub.2 (1)O.sub.3 0-40 RE.sub.2 (2)O.sub.3 0-1 Er.sub.2 O.sub.3 0.001-5 Yb.sub.2 O.sub.3 0-5 PbO 0-15 RO 0-20 ZnO 0-10 ZrO.sub.2 0-2 TiO.sub.2 0-2 Nb.sub.2 O.sub.5 0-10 Ta.sub.2 O.sub.5 0-10 P.sub.2 O.sub.5 0-5 B.sub.2 O.sub.3 0-15 As.sub.2 O.sub.3 0-10 Sb.sub.2 O.sub.3 0-20 Na.sub.2 Cl.sub.2 0-10 Bi.sub.2 O.sub.3 0-5, and ______________________________________up to 15 weight % fluorine in the form of at least one of a fluorinated component of the glass composition and a batch constituent selected from a group consisting of at least one of AlF.sub.3, REF.sub.3, NH.sub.5 F.sub.2, NaF, Na.sub.2 SiF.sub.6, Na.sub.3 AlF.sub.

Abstract: A silica glass composition and a method for manufacturing silica glass using the silica glass composition are provided. The silica glass composition includes: pyrogenetic silica having an average particle diameter of 5.times.10.sup.-3 to 1.times.10.sup.-1 .mu.m and a specific surface area of 50 to 400 m.sup.2 /g; and heat-treated silica, as an agglomerate of the pyrogenetic silica, having an average diameter of 2 to 15 .mu.m and a specific surface area less than that of the pyrogenetic silica. A high purity silica glass tube, in which cracking after drying rarely occurs and the shrinking ratio is remarkably decreased, can be obtained by using the silica glass composition according to the present invention. Also, a large silica glass tube can be manufactured by using the composition.

Abstract: Disclosed herein is a low phonon energy glass and a fiber made therefrom. e glass includes the following components given in mol percent:______________________________________ germanium 0.1-30 arsenic 0-40 X 0.01-20 Y 40-85 ______________________________________wherein X is selected from the group consisting of gallium, indium and mixtures thereof wherein Y is selected from the group consisting of selenium, and mixtures of selenium and up to 50% of sulfur substituted for selenium and the glass also contains 0.001-2 weight percent of a rare earth, based on the weight of said components. The fiber has a minimum loss of less than 5 dB/m.

Abstract: These glasses incorporate a combination of F and Al.sub.2 O.sub.3 to achieve even wider fluorescence and improved gain flatness. In addition, SPCVD incorporates large amounts of N into low-loss fiber whose high charge has an impact on rare earth behavior. The Surface Plasma Chemical Vapor Deposition (SPCVD) produces fiber preforms with high levels of F, Al.sub.2 O.sub.3, and N. These heavily fluorinated glasses provide much broader Er.sup.3+ emission than Type I or Type II silica for enhanced multichannel amplifiers. SPCVD successfully fluorinates silica with losses below 5 dB/km and increased Er.sup.3+ emission width.

Abstract: Chalcogenide glass fibers having a glass core with two cladding glass layers, the second cladding glass layer having a refractive index lower than that of the core glass and higher than that of the first cladding glass. The core glass does not contain germanium. Glass fiber having this core-cladding structure is mechanically strong and exhibits only small transmission loss of infrared light passing through the fiber.

Abstract: An optical fiber amplifier is formed from glass doped with praseodymium. The glass may include one or more of cadmium mixed halide, hafnium halides, geranium and silicon disulphide based vitreous materials or fluorozirconate glass fibers.

Abstract: A telluride glass with glass transition temperature above 150.degree. C., fference between the crystallization temperature and the glass transition temperature of above 200.degree. C., and extended transmission in the infrared region of radiation of up to 20 microns having, on mol basis, 20-60% tellurium, 10-50% arsenic, 4-35% germanium, 0.5-15% gallium, up to 15% iodine, and up to 30% selenium. All or part of the gallium can be replaced with indium and the glass can contain up to 5%, based on the weight of the glass components, of a rare earth ion to render the glass fluorescent. Optical fibers drawn from these glasses have shown mid infrared fluorescence and may have as a bright source of IR light.

Abstract: The invention relates to fluorine-containing silica glasses, and methods of their production. The silica glass may be used for an ultraviolet light optical system in which light in a wavelength region of 200 nm or less, such as an ArF (193 nm) excimer laser, is used. The invention also relates to a projection exposure apparatus containing fluorine-containing glass of the invention.

Abstract: A transparent class ceramic composition includes an oxide component, a rare earth component, a halide component, and a substantially pure rare earth-halide (e.g., REF.sub.3) crystal component. A method for making a transparent oxyfluoride glass includes preparing an oxyfluoride glass containing rare earth ions by a conventional melting method and subjecting the glass to a heat treatment thereby precipitating fluoride fine crystals containing a large amount of rare earth ions.

Abstract: The present invention relates to a transparent glass-ceramic article which includes a glass matrix and a crystalline phase of apatite crystals in the glass matrix. The present invention further relates to a method of producing the transparent glass-ceramic article.

Abstract: The specification describes a method for the manufacture of fluoride glass optical fibers which are covered with a protective coating of phosphate glass. The coating is produced by dipping the fluoride glass preform in a phosphate glass melt prior to drawing the optical fiber. The fluoride glass is ZBLAN. The phosphate glass has a glass transition temperature below 200.degree. C., which allows the dipping step to be carried out at a relatively low temperature where the preform temperature is maintained well below the crystallization temperature of the fluoride glass, and also where the viscosity of the fluoride glass preform is substantially higher than the viscosity of the phosphate glass coating material.

Abstract: A glass-ceramic material that is doped with rare-earths and is especially suitable for lasers and optical amplifiers is disclosed. The glass-ceramic material is optically non-scattering, and the doping with rare earths is essentially in the microcrystalline phase. The glass-ceramic material is preferably made up from complexes of metals having a valency of three or greater and of halides of rare earth ions having a valency of three or greater. The rare-earth ions include an optically active rare-earth ion.

Abstract: Disclosed are an optical fiber comprising a core and a cladding wherein the core is composed of a In-Ga-Cd-Pb halide glass and the clad composed of a halide glass possesses a refractive index of 1.515 or less, which has a large specific refractive index difference (.DELTA.n) and a large numerical aperture, and such an optical fiber as mentioned above wherein the core contains one or more activating ions as well as an optical fiber amplifier comprising a pumping source, a laser glass fiber and a means for introducing pumping light and signal light into the above laser glass fiber, wherein the laser glass fiber is the optical fiber of the present invention mentioned above.

Abstract: A selenide glass with improved mechanical and optical properties such as ended transmission in the infrared region of radiation having wavelengths beyond 15 microns; Tg in the region of 363.degree.-394.degree. C.; and thermal stability of 85.degree.-145.degree. C. based on the difference between T.sub.g and T.sub.x, comprising, on mol basis, 20-70% germanium selenide, 0.5-25% gallium selenide, indium selenide or mixtures thereof; and 5-50% of at least one alkaline earth in selenide form is described. A process for improving mechanical and optical properties of a selenide glass based on germanium selenide comprises the steps of mixing glass components, including a modifier in elemental or selenide form; melting the glass components to form a molten mixture; cooling the molten glass mixture to a solid state; annealing the solid glass; and cooling the annealed glass to about room temperature is also described.

Abstract: An improved optical glass fiber for transmitting mid infrared wavelength laser light in surgical instruments, includes a heavy-metal oxide component, preferably GeO.sub.2 doped with heavier cations and anions, and which is capable of delivering at least three watts of laser power continuously for more than ten minutes, without failure. This glass fiber has an .alpha.(dB/m) at 2.94 .mu.m of 10, preferably less, and can transmit at least 27% of the IR through a thickness of one foot.

Abstract: This invention relates to fluoride glass with a specific composition having wide infrared transmission. A fluoride optical fiber using this fluoride glass can give high efficiency with a low loss. The fluoride optical fiber having a second cladding on the outer periphery of a first cladding can adjust the refractive index of the first cladding suitably.

Abstract: Disclosed are laser glasses composed of a Ga--Na--S glasses doped with one or more kinds of activating ions, laser glass fibers comprising a core and a clad wherein the core is composed of the above-mentioned laser glasses of the present invention and optical fiber amplifiers comprising a pumping source, a laser glass fiber and a means for introducing pumping light and signal light into the laser glass fiber wherein the laser glass fiber is the above-mentioned laser glass fiber of the present invention. The laser glasses of the present invention show high radiative quantum efficiency and host glass stability and can be produced easily.

Abstract: A heavy metal fluoride glass composition for an optical fiber in mole percent, about: 20 to 40% InF.sub.3, 20 to 0% GaF.sub.3, 2 to 10% PbF.sub.2, 0 to 25% ZnF.sub.2, 0 to 25% CdF.sub.2,10 to 25% BaF.sub.2, 0 to 6% NaCl, 0 to 6% NaF, 0 to 7% SrF.sub.2 and 0 to 5% CaF.sub.2 ; the total of InF.sub.3 and GaF.sub.3 being about 40%; the total of BaF.sub.2, SrF.sub.2 and CaF.sub.2 being about 25%; the total of ZnF.sub.2 and CdF.sub.2 being about 25%, and the total of NaCl and NaF being about 6%; said composition being further doped with a lanthanide series heavy metal fluoride in amount up to about 1%.

Abstract: A preferred embodiment of a sulfide glass with improved mechanical and optical properties such as extended transmission in the infrared region of radiation having wavelengths of up to about 15 microns, Tg in the range of 370.degree.-550.degree. C., and thermal stability of 100.degree.-300.degree. C., containing, on mol basis, 36-72% germanium sulfide, 2-38% gallium sulfide and/or indium sulfide, and 26-62% of at least one modifier containing an alkaline earth sulfide. A process for making glass of improved mechanical and optical properties comprises the steps of mixing glass components, including an alkaline earth modifier in elemental or sulfide form; melting the glass components in an inert vessel contained in a sealed ampoule to form a molten mixture; cooling the molten glass mixture to a solid state; annealing the solid glass; and cooling the annealed glass to about room temperature.

Abstract: A sulfide glass with improved mechanical and optical properties such as ended transmission in the infrared region of radiation having wavelengths of up to about 15 microns; Tg in the region of 410.degree.-550.degree. C.; and thermal stability of 100.degree.-300.degree. C. based on the difference between T.sub.g and T.sub.x, comprising, on mol basis, 20-90% germanium sulfide, 0-60% gallium sulfide, and 5-60% of at least one modifier in sulfide form. A process for improving mechanical and optical properties of a sulfide glass based on gallium sulfide and/or germanium sulfide comprises the steps of mixing glass components, including a modifier in elemental or sulfide form; melting the glass components to form a molten mixture; cooling the molten glass mixture to a solid state; annealing the solid glass; and cooling the annealed glass to about room temperature.

Abstract: The present invention concerns a process for obtaining metal halides, in particular rare earth and/or alkali earth halides. This process consists of forming a homogeneous solution by mixing one or more rare earth and/or alkali earth halogenoalkoxides in an anhydrous organic solvent, and hydrolyzing this solution. The novel materials are obtained at room temperature and are in powder, fibre, film or bulk material form.

Abstract: Halide glasses having particular utility as hosts for praseodynmium in order to provide optical amplification by laser activity have a halide content provided as a small proportion, e.g., 1-10 percent, of choride with the remainder as fluoride. The metal content is similar to conventional ZBLAN glasses. The replacement of A1 by Y and In and/or the partial replacement of Na by Cs has synergistic benefits. PR.sup.3+ constitutes a good lasing species for amplifying telecommunication signals at 1300 nm using pumped radiation at 1020 nm.

Abstract: The present invention is directed to the preparation of two groups of transparent glass-ceramics exhibiting high optical clarity and containing essentially only one crystal phase. The first group consists essentially, in cation percent, of______________________________________ SiO.sub.2 20-35 PbF.sub.2 19-23 AlO.sub.1.5 10-20 YF.sub.3 3-7, CdF.sub.2 19-34 ______________________________________and the second group consists essentially, in cation percent, of ______________________________________ SiO.sub.2 20-35 PbF.sub.2 15-25 AlO.sub.1.5 10-20 YF.sub.3 3-7 CdF.sub.2 21-31 ZnF.sub.2 3-7. ______________________________________These glass-ceramics may be used to fabricate optical waveguide fibers. Also when doped with certain rare earth elements, notably Pr, Er, and Dy, the glass-ceramic materials may be used to fabricate optical amplifiers and lasers.

Abstract: A Cu-doped/Fe-doped low expansion glass ceramic composition comprising:______________________________________ Wt. % ______________________________________ SiO.sub.2 50-65 Al.sub.2 O.sub.3 18-27 P.sub.2 O.sub.5 0-10 Li.sub.2 O 2-6 Na.sub.2 O 0-2 K.sub.2 O 0-2 B.sub.2 O.sub.3 0-1 MgO 0-4 ZnO 0-5 CaO 0-4 BaO 0-5 TiO.sub.2 1-3 ZrO.sub.2 1-3 As.sub.2 O.sub.3 0-1.5 Sb.sub.2 O.sub.3 0-1.5 CuO 0-3 Fe.sub.2 O.sub.3 0-1 ______________________________________wherein the total amount of SiO.sub.2, Al.sub.2 O.sub.3 and P.sub.2 O.sub.5 is 80-89 wt. %, and said glass ceramic contains as a dopant 0.1-3 wt. % CuO, 0.1-1 wt. % Fe.sub.2 O.sub.3 or a combined CuO+Fe.sub.2 O.sub.3 amount of 0.1-4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

Abstract: The present invention is directed to the preparation of two groups of transparent glass-ceramics exhibiting high optical clarity and containing essentially only one crystal phase. The first group consists essentially, in cation percent, of______________________________________ SiO.sub.2 20-35 PbF.sub.2 19-23 AlO.sub.1.5 10-20 YF.sub.3 3-7, CdF.sub.2 19-34 ______________________________________and the second group consists essentially, in cation percent, of ______________________________________ SiO.sub.2 20-35 PbF.sub.2 15-25 AlO.sub.1.5 10-20 YF.sub.3 3-7 CdF.sub.2 21-31 ZnF.sub.2 3-7.

Abstract: Flourinated glasses containing indium fluoride and MF.sub.2 fluorides in at least 70 moles %, in which M denotes one or several elements of the group Ba, Sr, Ca, Pb. Said glasses contains, in the form of stabilizing elements, either 2 to 12 % gadolinium fluoride, or 2 to 10 % magnesium fluoride, or else a mixture of both fluorides in a proportion not exceeding 20 mole %. Variants of these compositions are also described.

Abstract: This invention is directed broadly to transparent glasses exhibiting excellent transmission far into the infrared region of the electromagnetic radiation spectrum, those glasses consisting essentially, expressed in terms of mole percent, of 40-80% Ga.sub.2 S.sub.3, 0-35% RS.sub.x, wherein R is at least one network forming cation selected from the group consisting of aluminum, antimony, arsenic, germanium, and indium, 1-50% Ln.sub.2 S.sub.3, wherein Ln is at least one cation selected from the group consisting of a rare earth metal cation and yttrium, 1-45% MS.sub.x, wherein M is at least one modifying metal cation selected from the group consisting of barium, cadmium, calcium, lead, lithium, mercury, potassium, silver, sodium, strontium, thallium, and tin, and 0-10% total chloride and/or fluoride. Glass compositions consisting essentially, expressed in terms of mole percent, of 5-30% Ga.sub.2 S.sub.3, 0-10% R.sub.2 S.sub.

Abstract: A chalcogenide glass that is doped with praseodymium and contains a rare earth metal is disclosed. The rare earth metal is at least 10 mole percent of the metals in the glass. The concentration of the praseodymium in the glass is at least 200 ppm. The chalcogenide glass, when formed into an amplifier for an optical fiber transmission system, efficiently amplifies optical signals in the signal band of 1.3 .mu.m.

Abstract: This invention is directed broadly to transparent glasses exhibiting excellent transmission far into the infrared region of the electromagnetic radiation spectrum, those glasses consisting essentially, expressed in terms of mole percent, of 40-80% Ga.sub.2 S.sub.3, 0-35% RS.sub.x, wherein R is at least one network forming cation selected from the group consisting of aluminum, antimony, arsenic, germanium, and indium, 1-50% Ln.sub.2 S.sub.3, wherein Ln is at least one cation selected from the group consisting of a rare earth metal cation and yttrium, 1-45% MS.sub.x, wherein M is at least one modifying metal cation selected from the group consisting of barium, cadmium, calcium, lead, lithium, mercury, potassium, silver, sodium, strontium, thallium, and tin, and 0-10% total chloride and/or fluoride. Glass compositions consisting essentially, expressed in terms of mole percent, of 5-30% Ga.sub.2 S.sub.3, 0-10% R.sub.2 S.sub.