Abstract: A method for reducing birefringence in a silicate waveguide structure having a waveguide core and cladding includes the step of selecting an irradiation energy that induces compaction in the cladding. The waveguide structure is then irradiated with radiation having an energy equal to the irradiation energy to induce a reduction in birefringence.

Abstract: A superemissive light pipe includes a photon transmitting optically transparent host having a body and oppositely arranged end portions. In one embodiment, superemissive material is disposed within the host and an optical cladding is disposed onto an outside surface portion of the host. The superemissive material emits photons upon thermal stimulation. The optical cladding reflects photons emitted by the superemissive material toward the host and directs the photons to the end portions. The optical cladding has an index of refraction different from that of the host. In another embodiment, a layer of superemissive material is interposed between the surface of the host and the optical cladding. A thermal energy source is either disposed internally within the host, in the form of radioisotopic particles that undergo nuclear decay, or externally outside of the light pipe, in the form of a general purpose heating source, to effect photon emission by the superemissive material.

Abstract: A highly oriented thin film of specific barium fluoride materials deposited at low temperatures are useful as Upconversion waveguides.

Abstract: A copolymer for optical fiber applications is the polymerization product of a mixture comprising a fluorinated itaconate and an alkyl (meth)acrylate.

Abstract: This invention relates to a family of rugged, non-toxic, high damage threshold, fiberizable, infrared transmitting germanate glasses that are suitable for medical laser delivery. They possess excellent visible transmission to utilize an aim beam in conjunction with the infrared laser. The glasses comprise (in mol %) 23.0-76.0% GeO.sub.2, 0-39.0% Ga.sub.2 O.sub.3, 3.0-51.0% SrO, 8.0-17.0% Ta.sub.2 O.sub.5, 0-23.0% Y.sub.2 O.sub.3, 0-35.0% ZnO, and optionally one or more of the following components; 0-11.0% TiO.sub.2, 0-20.0% Nb.sub.2 O.sub.5, 0-8.0% ZrO.sub.2, 0-13.0% Cs.sub.2 O, 0-10% MgO, 0-27% La.sub.2 O.sub.3, 0-25.0% Gd.sub.2 O.sub.3, 0-23.0% Yb.sub.2 O.sub.3. These glasses have intrinsic absorption coefficients of less than 0.137, 0.048, 0.024 and 0.021 dB/m at 2.94, 2.796, 2.71 and 2.69 .mu.m, respectively.

Abstract: A laser waveguide medium is provided comprising:a laser glass substrate wherein the substrate is a glass comprising (on an oxide composition basis):______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 50-70 Al.sub.2 O.sub.3 4-13 Na.sub.2 O 10-35 La.sub.2 O.sub.3 0-6 Ln.sub.2 O.sub.3 >0-6 R'O 0-20 R.sub.2 O 0-18 ______________________________________wherein Ln.sub.2 O.sub.3 is the sum of the oxides of active lasing lanthanides of atomic numbers 58-71, R'O is the sum of oxides of Mg, Ca, Cr, Ba, Zn and Pb, and R.sub.2 O is the sum of oxides of Li, K, Rb and Cs; anda waveguide region embedded in the substrate, the waveguide region having a higher refractive index than the substrate and the waveguide region having an inlet region through which light can enter and an outlet region through which light can exit.

Abstract: Fluoride glass-based optical fiber for an optical amplifier which contains rare earth metal ions in the core glass has a relative refractive index difference .DELTA.n between the core and the cladding of 1.4% or more. The core glass contains PbF.sub.2 in a proportion of 25 mol % or less based on the total composition of the core glass. The fluoride glass is doped with rare earth metal ions, and part of the fluorine in the glass may be substituted by at least one halogen Pr.sup.3+, Pr.sup.3+ --Yb.sup.3+, Pr.sup.3+ --Nd.sup.3+, or Pr.sup.3+ --Er.sup.3+ can be doped as the rare earth metal ions. Chlorine, bromine or iodine may be used as the halogen.

Abstract: A fiber optical source of stimulated optical radiation comprises an optical fiber which includes a core doped with laser material having optical gain in two wavelength regions, the fiber additionally including a material in optical communication with said laser material in such a manner as to absorb radiation emitted from said laser material within one of said wavelength regions.

Abstract: A transparent molded article for optical applications made from silicon nitride and a coating thereon of oxidic silicon nitride formed by chemical reaction of the silicon nitride with oxygen. The moldings can be shaped, depending on the area of application, to give various articles, for example optical waveguides, prisms, sensor elements or lenses, and are used in all areas where high optical demands are made.

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: An optical amplifier having a doped fluoride glass optical fiber and a process for producing such an amplifier. To produce the doped fluoride glass fiber amplifier which is operable to amplify a light signal (S), an optical multiplexer (4) is produced having on the one hand two silica fibres (6, 8) and on the other a fluoride glass fiber (2), whereof at least one section is doped and an optical coupling is brought about between the fluoride glass fiber and at least one other silica fibre (12, 14).

Abstract: A quartz-based optical fiber with a lens, wherein a lens shaped in a curved surface is directly formed on an end surface, and its manufacturing method are provided, the quartz-based optical fiber with a lens having a lens section formed by a projecting core shaped in a curved surface on the end surface, the lens section being produced by immersing the end surface section of the quartz-based optical fiber, which consists of a core and a clad having a composition in which the etching speed is higher than that of the core when a hydrofluoric acid solution is applied, in the hydrofluoric acid solution to cause a core shaped in a truncated cone to project from the end surface of said quartz-based optical fiber, then heating and melting the core shaped in the truncated cone and the vicinity thereof, thus changing the truncated cone shape into a curved surface shape.

Abstract: An optical waveguide is created using the process of ion beam deposition resulting in a waveguide with low propagation loss, mode discrimination, and gain characteristics. The waveguide is made up of a multilayer stack which is deposited upon a thermally stable substrate, wherein the multilayer stack comprises alternating layers of a first material and a second material. The layers of second material are doped with a rare earth material. By pumping the waveguide with a pump light source, interaction between the pump light and the rare earth material within the waveguide causes amplification or gain of a first optical signal. Ion beam deposition is used to fabricate the waveguide, therefore production of a high quality rare earth doped waveguide is possible. Furthermore, the waveguide is made using batch processing thus reducing costs.

Abstract: We disclose a new optical TE-TM mode splitter on lithium niobate. The splitter is fabricated by using an asymmetric Y-junction structure which is composed of a straight waveguide, and two branch waveguides. The straight waveguide is the input one that can guide randomly-polarized light (i.e. both TE and TM modes). The two branch waveguides are the output ones, and one of them can guide only the TE mode, the other can guide only the TM mode. Because the output waveguides can individually guide the TE and TM modes, the input modes are then split by the branch waveguides. The input waveguide is fabricated by diffusing titanium into lithium niobate. The two output waveguides are made by nickel indiffusion and magnesium-oxide induced lithium outdiffusion or proton exchanged techniques.

Abstract: A system for producing an optical gain, the system including a host having a light conducting path doped with thulium, holmium, and at least one rare earth selected from the group consisting of europium and terbium in respective amounts sufficient to produce an optical gain by energizing the thulium to a .sup.3 H.sub.4 state to produce an optical gain by a .sup.3 H.sub.4 -.sup.3 F.sub.4 transition, producing a 1.47 .mu.m wavelength output. There is subsequent energy transfer from the .sup.3 F.sub.4 state of the thulium to a .sup.5 I.sub.7 state of the holmium, and energy transfer from the .sup.5 I.sub.7 state to the rare earth selected from the group consisting of europium and terbium. The system can include oscillator, amplifier, and superluminescence source configurations. A method for making and a method for using the system are included.

Abstract: An optically active device comprising an optical fiber, a light source and an optical device is disclosed. The optical fiber comprises a core made of an optical functioning glass doped with Pr.sup.3+ as an active ion and transmits light at a first wavelength. The light source generates excitation light at a second wavelength shorter than the first wavelength. The optical device directs the excitation light from the light source into the optical fiber. Then, Pr.sup.3+ in the core of the optical fiber is stimulated to emit light at the second wavelength. As a result, an optical function such as optical amplification can be effected at the second wavelength.

Abstract: An object of this invention is to provide an optical filter which has higher mass-producibility and economy. This feature can be realized by doped a rare earth element into the region made of a glass material which can transmit light. In a case that Er and Tm are doped as the rare earth element into the region, a ratio .alpha..sub.Er /.alpha..sub.Tm between a contribution .alpha..sub.Er of Er to attenuation and a contribution .alpha..sub.Tm of Tm to attenuation is set in a range from about 1 to 1/25 for a 1.5 .mu.m band range, whereby attenuation in this wavelength range is retained above 50 dB/m to realize required cutoff function.

Abstract: Devices for controlling high frequency signals such as optic or electric signals are disclosed which utilize guided and/or reflected surface acoustic waves. The devices preferably use crystalline substrates modified (e.g., by ion exchange to increase mass density) to contain acoustic reflectors and/or continuous acoustic waveguiding channels (optionally, in combination with optical features such as optical waveguiding channels) and interdigital transducers deposited thereon to provide frequency generation (and reception where high frequency electrical signals are controlled). The preferred crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves, such as MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.

Abstract: A semiconductor waveguide structure of the II-VI group compound semiconductor made of the II group element and the VI group element. The waveguide structure includes a waveguide layer and clad layers which puts the waveguide layer therebetween. The waveguide layer has a refractive index larger than a refractive index of each clad layer. At least one of the clad layers contains the element Cd. With such an arrangement, the refractive index of one clad layer is established to be different from that of the other clad layer. In such a case, it is preferable that the semiconductor waveguide structure comprises at least two waveguide layers which are adjacent to each other and that the structure has either one of the features as follows: each refractive index of the waveguide layers varies stepwise at each boundary surface of the layers; the refractive index of at least one of the waveguide layers varies so as to be inclined; and super lattice layers are formed between the clad layer and the waveguide layers.

Abstract: A wavelength multiplexing tapered fused fibre coupler is used to splice a second length of optical amplifier fibre between first and third lengths in such a way that pump power bypasses it. The second length is therefore unpumped and acts as a notch filter smoothing out the spectral gain characteristic of the first and third lengths.

Abstract: Optical wave-guides, e.g. fibres, for use as photonic amplifiers have a path region partly or, preferably, wholly composed as a silica/germania glass with 0.1 to 5000 ppm mole of Er.sup.3+ as a lasing additive and alumina to adjust the bandwidth, the Ge:Al mole ratio being more than 2.8, e.g. 1:0.001 to 0.25. It is surprising that low amounts of alumina have a useful and significant effect on the lasing bandwidth whereby frequency division multiplex is facilitated.

Abstract: A fiber probe device includes a fiber segment that has at least three sections. An uppermost section has the largest diameter; an intermediate section has an intermediate diameter, and a lowest section (tip) has the smallest diameter. The presence of the intermediate section enables control over the stiffness of the section located immediately above the tip as well as control over the mechanical resonance characteristic of the probe device when it scans a sample surface to be measured.

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: There is disclosed an optical waveguide comprising a core portion made of a light propagating material and a cladding portion, a first dopant and a second dopant being induced into said core portion, the first dopant having a function of increasing a refractive index of the light propagating material and having a first thermal diffusion coefficient to said light propagating material, the second dopant having a function of decreasing the refractive index of said light propagating material and having a second thermal diffusion coefficient to the light propagating material larger than the first thermal diffusion coefficient under a predetermined temperature.

Abstract: A method of fabricating a microwave waveguide component wherein a plurality of joinable thermoplastic members are first formed. The members, when joined, comprise a microwave waveguide component having an internal surface that is adapted to be plated. The thermoplastic members are then bonded together. Then, the internal surface is plated to form the finished microwave waveguide component. The present method forms microwave components from plated, injection molded thermoplastic and reaction injection molded thermosetting plastics. In particular, the plastic components made using the present invention exhibit comparable electrical performance, as measured by voltage standing wave ratio (VSWR) and insertion loss, decreased device weight and cost, and reliable and repeatable manufacturability when compared with devices formed using metals, conventional thermosetting plastics that have been metallized, and molded, plated and soldered thermoplastics.

Abstract: An optical functioning glass for enabling optical amplification at 1.3-.mu.m wavelength band or increasing efficiency of the amplification is disclosed. The optical functioning glass contains Nd.sup.3+ as an active material and uranium, both of which are doped in a multi-component function glass serving as a host glass. Since uranium is doped in the optical functioning glass, light emission of Nd.sup.3+ in the 1.06-.mu.m wavelength band can be absorbed by uranium. A decrease in efficiency of induced emission in a 1.3-.mu.m wavelength band can be prevented, and an optical functioning glass suitable for optical amplification in the 1.3-.mu.m wavelength band can be obtained. When a fiber is formed using the optical functioning glass as a core, a low-threshold, high-gain fiber amplifier, fiber laser, and the like can be obtained.

Abstract: An optical fiber includes an optical fiber element having a core layer and a cladding layer formed on the core layer, and a coating layer having a refractive index lower than at least the refractive index of the cladding layer, or a coating layer including at least one of a predetermined saturated higher fatty acid and alkylpolysiloxane.

Abstract: An optical waveguide is disclosed with a substantially planar substrate and a waveguide layer applied to the substrate. The invention resides in that the substrate consists of a synthetic resin or of a material having a high organic proportion. This has the advantage that the high index of refraction of the inorganic waveguide layer is combined with the material properties of the synthetic resin substrate, such as, for example, breaking resistance, plastic and thermoplastic moldability, photochemical structuring ability, and others.

Abstract: Optical fiber composed of a glass doped with at least laser-active ions of an element from the rare earths. An optical fiber of glass, preferably a HMF glass, doped with Tm.sup.3+ is operated at 1.48 .mu.m as a fiber laser or amplifier on the laser transition .sup.3 F.sub.4 -.sup.3 H.sub.4. Since this thereby involves a self-saturating transition, the terminal level is emptied in accelerated fashion for a continuous wave mode by co-doping with de-activators, preferably Ho.sup.3+, Tb.sup.3+, Eu.sup.3+ and/or Pr.sup.3+ ions. The pump light wavelength can be selected from the wavelength range from 700 through 890 nm of GaAlAs emission. The optical fiber can be used in optical amplifiers or fiber amplifiers.

Abstract: This invention provides a fiber waveguide with a liquid crystal core. The liquid crystals are aligned in layers with molecular directors approximately parallel to each other. An electric field can be applied to the liquid crystal core to provide linear and nonlinear optical modulation. Alone or in combination with polarizers, reflectors, and birefringent elements, the waveguide of this invention provides phase, polarization and intensity modulation, spectral filtering, and second harmonic generation.

Abstract: A multi-waveguide cylindrical optical conductor for telecommunications cable, the conductor comprising a plurality of optical fibers, each of which is a unit cylindrical fiber constituted by a core and by cladding, the unit fibers are all connected together by silica after a fiber-drawing operation, wherein said core of said unit cylindrical fiber has a diameter of about 8 .mu.m to 10 .mu.m, wherein said cladding has an outside diameter lying in the range 25 .mu.m to 35 .mu.m, and wherein all of the cores of said unit fibers are either situated regularly on generator lines of a cylinder having the same axis as said conductor, or else are parallel with one another and are coplanar. An optical conductor can thus be obtained having an outside diameter of 125 .mu.m and containing six waveguides each having a diameter of about 25 .mu.m to 35 .mu.m.

Abstract: Fluoride glass-based optical fiber for an optical amplifier which contains rare earth metal ions in the core glass has a relative refractive index difference .DELTA..sub.n between the core and the cladding of 1.4% or more. The core glass contains PbF.sub.2 in a proportion of 25 mol % or less based on the total composition of the core glass . The fluoride glass is doped with rare earth metal ions, and part of the fluorine in the glass may be substituted by at least one halogen. Pr.sup.3+, Pr.sup.3+ --Yb.sup.3+, Pr.sup.3+ --Nd.sup.3+, or Pr.sup.3+ --Er.sup.3+ can be doped as the rare earth metal ions. Chlorine, bromine or iodine may be used as the halogen.

Abstract: A gradient index optical element has at least one first metal dopant selected from the group consisting of La, Y, Ga, In, Ge, Sn, Zn, Zr, Ba, Ca, As, Sr, Gd and Be distributed at a concentration gradient in a glass medium. The concentration gradient of the first metal dopant defines a slope having a direction. At least one second metal dopant different from the first metal dopant and selected from the group consisting of Bi, Sb, Nb, Ti, Ta, Pb, Tl, Zr, In, Sn, Y, Ba, Ca and Sr is distributed at a concentration gradient in the glass medium. The concentration gradient of the second metal dopant defines a slope smaller than the slope of the concentration gradient of the first metal dopant. The slope of the concentration gradient of the second metal dopant is in the same direction as the slope of the concentration gradient of the first metal dopant.

Abstract: An evanescent wave sensor and method for use in analyzing one or more media, the sensor including a waveguide having first and second wave propagating surfaces. The waveguide propagates an input signal along the waveguide between the first and second surfaces. The first surface receives a first radiation signal which indicates the presence of a first analyte, and the second surface receives a second radiation signal representing one or both of a second analyte and a reference. The first and second surfaces can both be contacted with a single medium, or with two separate media, and one or more output signals can be detected.

Abstract: An optically active device comprising an optical fiber, a light source and a coupler is disclosed. The optical fiber has a core made of a silicate glass containing Rb and/or Cs oxide. The core is doped with Nd.sup.3+ as an active ion and transmits light at 1.3 .mu.m band. The light source generates excitation light at 0.8 .mu.m. The coupler directs the excitation light from the light source into the core of the optical fiber. A signal light or a spontaneous light at 1.3 .mu.m band which is transmitted in the core stimulates Nd.sup.3+ to emit light at 1.3 .mu.m band. As a result an optical function such as optical amplification can be effected at 1.3 .mu.m band.

Abstract: Previous efforts to measure polarization dependent loss of optical components have been limited in uncertainty to more than 0.01 dB. This is because the power meter used in a test set contains polarization dependent loss which adversely affects the final readings. It is here disclosed that an unpumped erbium doped fiber can convert a received polarized signal into unpolarized amplified spontaneous emission of a longer wavelength if the fiber is of sufficient length to absorb the received signal. By locating the inventive unpumped erbium doped fiber upstream of the power meter of a test set, the polarized signal to the power meter is coverted to an unpolarized signal and, therefore, the polarization dependent loss of the power meter can not influence the measurement obtained.

Abstract: A light waveguide lead has at least one light waveguide accommodated within a protective sheath and this light waveguide is embedded in a pasty filling compound characterized by small balls being added to the compound, which balls are composed of a different material than the filling compound material. The diameter of the small balls and the number are selected so that the light waveguide has a displaceability within the filling compound that is adequate to allow stranding in other processes to the light waveguide lead.

Abstract: A silica glass optical fiber superior in resistance to ultraviolet rays, which fiber comprises a doped silica glass cladding layer formed on a silica glass core, said silica glass core having an OH content of 10-1000 ppm, a fluorine content of 50-5000 ppm, and being substantially free of chlorine.

Abstract: Optical amplifiers and other active optical components along a signal distribution path are remotely pumped by a common pump laser. The pump energy can be transmitted over the signal path or over a separate pump path. Pumping of rare earth doped optical fiber amplifiers, such as erbium doped fiber amplifiers is illustrated. The pump energy can be provided at about 1480 nanometers to take advantage of reduced attenuation at this wavelength along the fiber path.

Abstract: A core of a fluorozirconate optical fiber is doped with rare earth ions, namely trivalent Dy ions. The Dy ion makes an absorption transition with excitation light generated by an 800 nm semiconductor laser module. Then the Dy ion undergoes transitions, namely a nonradiative transition involving phonon emission, a transition to a metastable excited level, and a radiative transition wherein radiation corresponding to the 1.28 .mu.m to 1.35 .mu.m range occurs, thereafter returning to its ground state level. The Dy ion having an electrovalence of three can be pumped with a high-output 800 nm semiconductor laser module and is not subject to saturation at a lower energy level of population inversion. Using an optical fiber of the invention, a higher gain is obtained in the region of 1.3 .mu.m telecommunications window.

Abstract: A waveguide structure is directly extruded onto a surface from a nozzle placed a predetermined distance above the surface and which is moved relative to the surface, preferably by means of a translation table. The predetermined distance is preferably maintained constant and the speed of relative motion regulated to achieve a uniform degree of molecular orientation within the extruded material, thus maintaining a sufficiently uniform refractive index along the axis of the waveguide. Partitions within the nozzle allow the formation of a layered waveguide or the simultaneous formation of concentric cladding or protective layers. The waveguides are advantageously formed as a curtain which is later patterned, by direct writing on the surface or between chips mounted on an electronic module.

Abstract: Polyimide optical waveguide structures comprising a core within a cladding wherein at least one of the core and the cladding is a polyimide containing 6FDA, BTDA, an aromatic diamine having bulky methyl groups ortho to the amine, and a co-diamine wherein the polyimides have the properties of low optical loss, low optical absorbance, controllable refractive index, and high thermal stability, and wherein the polyimides are photosensitive and solvent resistant.

Abstract: A component for the transmission of light of high energy density with a wavelength between 250 nm and 400 nm is made of synthetic, high-purity fused vitreous silica having a hydroxyl ion content in the range between 50 ppm and 1200 ppm and an under-stoichiometric content of oxygen for the achievement of a minimal transmission variation in the transmission of the light.

Abstract: Said medium is a halide glass (2, 8, 12, 20) containing uranium ions at least partly in the form U.sup.3+ and having, at least at one point of a region of the near infrared between 2.2 and 3.4 micrometers, an optical attenuation not exceeding 0.01 cm.sup.-1. For the production thereof, preparation takes place of a halide glass containing uranium ions, at least partly in the form U.sup.4+ and/or U.sup.5+, and having at least at this point the aforementioned attenuation. The glass is exposed to ionizing radiation able to produce trivalent uranium ions from the uranium ions of the prepared glass. Application to the production of optical guides, whereof the guiding parts are formed from such a medium.

Abstract: The present invention is directed to silver halide fibers. In one embodiment, the fiber has been doped with AgI or a metal compound of the formula MY wherein M is selected from Li, Na, K, Rb, Cr, Mg, Ca, St, Ba, Cd or Hg, and Y is selected from Cl, Br, or I. The fiber has large, elongated grain core structure and decreased infrared transmission losses and a more even/cladding interface in cladded embodiments.

Abstract: A system for producing an optical gain. The system includes an optical fiber having a core and a cladding, the core being doped with Pr.sup.3+ ; and a source producing light to energize the Pr.sup.3+ to the .sup.1 G.sub.4 state and produce an optical gain by a .sup.1 G.sub.4 -.sup.3 H.sub.5 transition at a wavelength in the range of 1.25 to 1.34 microns. The system also includes a method of making and a method of using the same.

Abstract: Optical fibers and glass composition comprising a mixture of barium oxide, gallium oxide, germanium oxide, and a modifying agent selected from lanthium oxide, indium oxide, and mixtures thereof; molar ratio of barium oxide to gallium oxide is from about 4:1 to about 1:1, preferably 2:1 to 1, and especially about 1:1; amount of germanium oxide is at least 40 mole percent, preferably 60 to 95 mole percent, and especially 65 to 90 mole percent; about 0.1 to about 5 mole percent, preferably 0.5 to 4, of gallium oxide is replaced with the modifying agent. The optical fibers made from the glass composition defined herein, with or without the modifying agent, have light transmission wavelength band of about 0.3 to 4 microns; lower optical loss than silica-based optical fibers, the minimum optical loss of the novel fibers having the potential of 0.05 dB/km at 2 microns.

Abstract: The present invention provides a mode field conversion fiber component formed by fusion-connecting connection end surfaces of two optical components having different mode fields. The mode fields of the two optical components are conformed to each other at the connection end surfaces, and are continuously varied near the connection end surfaces. The present invention also provides a method for manufacturing a mode field conversion fiber component, having the steps of butting connection end surfaces of two optical fibers having different mode fields, fusion-connecting the connection end surfaces of the two optical fibers, and heating a fusion-connecting portion of the connection end surfaces, diffusing core dopant, and conforming the mode fields of the two optical fibers.

Abstract: A system for producing an optical gain, the system including a host having a light conducting path doped with thulium, holmium, and at least one rare earth selected from the group consisting of europium and terbium in respective amounts sufficient to produce an optical gain by energizing the thulium to a .sup.3 H.sub.4 state to produce an optical gain by a .sup.3 H.sub.4 -.sup.3 F.sub.4 transition, producing a 1.47 .mu.m wavelength output. There is subsequent energy transfer from the .sup.3 F.sub.4 state of the thulium to a .sup.5 I.sub.7 state of the holmium, and energy transfer from the .sup.5 I.sub.7 state to the rare earth selected from the group consisting of europium and terbium. The system can include oscillator, amplifier, and superluminescence source configurations. A method for making and a method for using the system are included.

Abstract: An optical waveguide having a core/sheath structure whose sheath comprises a terpolymer based on vinylidene fluoride, tetrafluoroethylene and hexafluorpropylene, is suitable for transmission paths of ca. 10 to 100 m an can also be used at a temperature of above 100.degree. C. without significant reduction of the transmission path.