Abstract: The invention relates to a filtering media having a photocatalytic action which has a thickness of at least 2 mm, which is homogeneous and which is devoid of orifice apparent to the naked eye, comprising a felt of inorganic fibers, the fibers of which are coated with a coating comprising a catalyst having a photocatalytic action, said felt exhibiting a weight per unit area of between 30 and 80 g/m2, said coating representing 5 to 80% of the weight of said media, said media exhibiting a gas pressure drop of less than 150 Pa at 1 m/s in unpleated condition. This media is intended to be incorporated in a purifier of gas, such as air, furthermore comprising a system for illuminating said media with UV radiation. The media exhibits an excellent purification efficiency and a very low pressure drop.

Abstract: Light diffusing optical fibers and methods for producing light diffusing optical fibers are disclosed. In one embodiment, a light diffusing optical fiber includes a core portion formed from silica glass and comprising a plurality of helical void randomly distributed in the core portion of the optical fiber and wrapped around the long axis of the optical fiber. A pitch of the helical voids may vary along the axial length of the light diffusing optical fiber in order to achieve the desired illumination along the length of the optical fiber. A cladding may surround the core portion. Light guided by the core portion is scattered by the helical voids radially outward, through the cladding, such that the light diffusing optical fiber emits light with a predetermined intensity over an axial length of the light diffusing optical fiber, the light diffusing optical fiber having a scattering induced attenuation loss greater than about 0.2 dB/m at a wavelength of 550 nm.

Abstract: [Object] The present invention has the object of providing an optical fiber enabling high-speed communication, that exhibits superior transparency and excellent flexibility, and that includes trichloroethyl methacrylate as a main component of the core portion monomer. [Means for Solving Problem] An optical fiber configured from a core portion and a cladding portion disposed on an outer periphery of the core portion, wherein the core portion is formed by a main constituent component of a polymer of monomers that include at least 70 wt % of trichloroethyl methacrylate (TCEMA), the cladding portion is formed by a main constituent component of a polymer of monomers which include at least 20 wt % of methyl methacrylate (MMA).

Abstract: In various examples, a semi-guiding optical fiber includes a core having a high aspect ratio including first and second wide surface interfaces, and first and second narrow edge interfaces. The core has a slow axis parallel to the first and second wide surface interfaces, and a refractive index. The fiber also includes first and second signal claddings positioned in contact with the first and second wide surfaces of the core, respectively. The first and second signal claddings have a spatial refractive index profile having: i) a minimum value at a longitudinal axis of the core, ii) a maximum value substantially equal to the refractive index of the core at the first and second narrow edge interfaces of the core, and iii) intermediate values gradually increasing from the minimum value to the maximum value as distance from the longitudinal axis increases along the slow axis of the fiber.

Abstract: An apparatus may include a waveguide. The waveguide may include a distal end surface which may be substantially normal to a centerline of a distal end portion of the waveguide. The apparatus may further include a cover which may be coupled to a portion of the waveguide. The cover may include a portion distal to the distal end surface of the waveguide, and the portion of the cover may be made of a material which may be configured to be removed when exposed to electromagnetic radiation emitted from a portion of the distal end surface of the waveguide.

Abstract: Disclosed is a reduced-diameter optical fiber that employs a novel coating system. When combined with a bend-insensitive glass fiber, the novel coating system according to the present invention yields an optical fiber having exceptionally low losses. The coating system features (i) a softer primary coating with excellent low-temperature characteristics to protect against microbending in any environment and in the toughest physical situations and, optionally, (ii) a colored secondary coating possessing enhanced color strength and vividness. The secondary coating provides improved ribbon characteristics for structures that are robust, yet easily entered (i.e., separated and stripped). The optional dual coating is specifically balanced for superior heat stripping in fiber ribbons, with virtually no residue left behind on the glass. This facilitates fast splicing and terminations.

Abstract: In various embodiments, a semi-guiding optical fiber includes a core having a first refractive index and a high aspect ratio elongated cross-section along a slow axis direction. First and second signal claddings having a second refractive index sandwich the core. A third cladding having a third refractive index substantially surrounds at least side edges of the core. The first refractive index of the core, the third refractive index of the third cladding, and/or the second refractive index of the first and second signal claddings, are selected so as to maximize a differential loss between a lowest order mode propagating in the optical fiber and next order modes so as to discriminate in favor of the lowest order mode and against the next order modes.

Abstract: A light coupling system includes a laser light source and an optical fiber. The optical fiber includes a fiber core having a central optical axis, and a cladding layer surrounding the fiber core. The optical fiber has a distal end surface covering a distal end of the fiber core and a distal end of the cladding layer. The distal end surface includes an inner conical surface centered on the central optical axis, and an outer frustoconical surface centered on the central optical axis and surrounding and adjoining the inner conical surface. A cone angle of the inner conical surface is greater than a cone angle of the outer frustoconical surface. The distal end surface of the optical fiber faces toward the laser light source.

Abstract: A polarization-maintaining optical fiber of the present invention includes a core, a pair of stress-applying parts provided on both sides of the core, and a cladding surrounding the core and the stress-applying parts, and is used in a wavelength range of 400 to 680 nm. The diameter of the cladding is 125 ?m, the diameter of the stress-applying part is 33 to 37 ?m, a distance between the pair of stress-applying parts is 8.6 to 15.4 ?m, a relative refractive index difference between the core and the cladding is 0.35 to 0.45%, and a cut-off wavelength is less than or equal to 400 nm.

Abstract: A resin composition for an optical waveguide is provided, which permits easy formation of a core pattern using an alkali developing liquid and suppresses degradation of the alkali developing liquid. An optical waveguide produced by using the resin composition is provided. The resin composition comprises: (A) an alkali soluble resin, as a major component, having a structural unit represented by formula (1): wherein R1, R2 and R3, which may be the same or different, are each a hydrogen atom or a methyl group; R5 and R6, which may be the same or different, are each a hydrogen atom or a methyl group; R4 is and m+n+p=1, m>0, n>0 and p>0; and (B) a photopolymerization initiator. The optical waveguide includes a substrate, a cladding layer provided thereon, and a core portion provided in the cladding layer for transmitting an optical signal.

Abstract: A low-loss optical fiber over wide wavelength range includes a transmission loss of less than or equal to 40 dB/km in a whole wavelength range of 400-1400 nm, and being manufactured by drawing an optical fiber preform including a core composed of a silica glass having a hydroxyl-group concentration of less than or equal to 1 ppm and a cladding composed of a silica glass having a fluorine concentration of more than or equal to 3.2 wt %.

Abstract: The present invention relates to a GI-type multi-mode optical fiber in which the outer diameter of the core is 47.5 to 52.5 ?m or 60 to 65 ?m, or to a bend resistant multi-mode optical fiber provided with resistance against property fluctuation caused by the bending of the multi-mode optical fiber by providing a trench portion having a low refractive index at the outer periphery of the core. In the multi-mode optical fiber, both the maximum tensile stress and the maximum compressive stress in the optical axis direction remaining in the core are 50 MPa or less.

Abstract: An optical fiber polarimetric chemical sensor for capillary gas chromatography in which a sample fluid is injected into a capillary in the form of a periodic pulse train. Each individual pulse defines a moving polarization coupling zone that affects the polarization state of the light propagating in a birefringent optical waveguide that includes the capillary. The spacing between consecutive coupling zones can be made equal to the polarization beat length of the waveguide when the injection frequency of the pulses is properly selected, thus defining a resonance condition for a given analyte. The contributions of the successive coupling zones present along the length of the capillary then add up in phase, thus resulting in a detected optical signal having an enhanced amplitude peak at the injection frequency. In this manner, the sensitivity can be enhanced.

Abstract: The present invention relates to an optical fiber for an SPR sensor, characterized in that the optical fiber is comprised of a core layer and a cladding layer surrounding the core layer, and the cladding layer is doped with metal nanoparticles.

Abstract: An optical waveguide forming epoxy resin composition is free from a diluent component irrelevant to a curing reaction, and comprises: (A) a liquid epoxy resin; and (B) a photoacid generator; wherein the liquid epoxy resin (A) comprises a liquid epoxy resin represented by the following general formula (1) in a proportion of 40 to 75 wt % based on the overall amount of a resin component: wherein R1 and R2 are each a hydrogen atom or a methyl group; R3 to R6 are each a hydrogen atom, a methyl group, a chlorine atom or a bromine atom; X is a C2 to C15 alkylene group, an ethyleneoxy group, a di(ethyleneoxy) group, a tri(ethyleneoxy) group, a propyleneoxy group, a propyleneoxypropyl group, a di(propyleneoxy)propyl group or a tri(propyleneoxy)propyl group; and n is a natural number and has an average value of 1.2 to 5.

Abstract: Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprising cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

Abstract: In order to decrease transmission loss caused by Rayleigh scattering in an optical fiber, without negatively affecting the curvature loss, provided is an optical fiber comprising a core at a center thereof, a low refractive index layer that is adjacent to the core and covers an outer circumference of the core, and a cladding that is adjacent to the low refractive index layer and covers an outer circumference of the low refractive index layer, wherein a refractive index of the core is higher than a refractive index of the cladding, a refractive index of the low refractive index layer is lower than the refractive index of the cladding, and the refractive index of the low refractive index layer decreases in a direction from an inner portion of the low refractive index layer to an outer portion of the low refractive index layer.

Abstract: An optical fiber of the invention satisfies ?core>?ic>?tmax>?tmin, ?0.15%??tmax>?tmin??0.7%, and 0.45?(rtmax?rin)/(rout?rin)?0.9 where the relative refractive index difference of the core is ?core, the relative refractive index difference of the internal cladding coat is ?ic, the relative refractive index difference of a highest refractive index layer in the trench coating is ?tmax, the relative refractive index difference of a lowest refractive index layer in the trench coating is ?tmin, the radius of an internal edge of the trench coating is rin, the radius of an external edge of the trench coating is rout, and the radius of an internal edge of a highest refractive index layer in the trench coating is rtmax and where the relative refractive index differences are based on a refractive index of the outermost cladding coat.

Abstract: Methods of manufacturing optical devices are disclosed. The method includes providing a structure-forming fiber bonded to at least one other optical component, the structure-forming fiber having a preferentially-etchable portion including at least one radial etching boundary and at least one axial etching boundary, and etching the preferentially-etchable portion to the radial and axial etching boundaries to produce a precise optical structure. The preferentially-etchable portion may be removed through one or more radial openings in the structure-forming fiber. Numerous other aspects are provided.

Abstract: Various embodiments of optical fiber designs and fabrication processes for ultra small core fibers (USCF) are disclosed. In some embodiments, the USCF includes a core that is at least partially surrounded by a region comprising first features. The USCF further includes a second region at least partially surrounding the first region. The second region includes second features. In an embodiment, the first features are smaller than the second features, and the second features have a filling fraction greater than about 90 percent. The first features and/or the second features may include air holes. Embodiments of the USCF may provide dispersion tailoring. Embodiments of the USCF may be used with nonlinear optical devices configured to provide, for example, a frequency comb or a supercontinuum.

Abstract: A manufacturing method of a photonic band gap fiber which includes measuring a hole diameter d0 and a distance-between-holes ?0 in a preliminary experiment capillary body by first drawing a preliminary experiment preform, calculating a confinement loss to a normalized wavelength ?/? being a wavelength ? normalized by an optional distance-between-holes ? using a ratio d0/?0 and the optional distance-between-holes ? as design parameters, setting a distance-between-holes by calculating the set distance-between-holes ?1 to a desired transmission wavelength ?1 of a photonic band gap fiber to be manufactured using a value of the normalized wavelength ?/? in which the confinement loss becomes about a minimum value, and second drawing a preform for a photonic band gap fiber by using the same members as those of the preliminary experiment preform and by setting a distance-between-holes to the set distance-between-holes ?1, in a drawing temperature condition used for the first drawing.

Abstract: A single-mode optical fiber for use as a stub fiber in an optical fiber connector is disclosed. The optical fiber is configured minimize the adverse effects of multipath interference (MPI) that can arise in a short, single-mode conventional stub fiber that has a large group index difference. The optical fiber is also configured to have a mode-field diameter that is substantially the same as that of single-mode optical fibers intended for use as field fiber in a mechanical splice connector, along with a cutoff wavelength ?C?1200 nm. An optical fiber connector that uses the optical fiber as a stub fiber is also disclosed.

Abstract: An embodiment relates to image sensor comprising one or more nanowires on a substrate of a cavity, the nanowire being configured to transmit a first portion of an electromagnetic radiation beam incident on the sensor, and the substrate that absorbs a second portion of the electromagnetic radiation beam incident on the sensor, wherein the first portion is substantially different from the second portion. The substrate could have a anti-reflective material. The ratio of a diameter of the cavity to a diameter of the nanowire could be at less than about 10.

Abstract: A fiber-inline MZI device for temperature sensing or refractive index (RI) sensing, the device comprising: a section of a Photonic Crystal Fiber (PCF) having at least two air holes infiltrated with a liquid analyte to form a waveguide channel, the liquid analyte forming rods in the PCF; wherein the rods leave an interference fringe pattern in the transmission spectrum when light is injected into the PCF, and fringe dips are tracked over a wide wavelength range in order to sense the temperature or refractive index.

Abstract: An optical fiber includes a core portion and a cladding portion that is formed around an outer periphery of the core portion and has a refractive index lower than a maximum refractive index of the core portion. As characteristics at a wavelength of 1550 nm, an effective core area in a fundamental propagation mode is 120 ?m2 or larger, an effective core area in a first higher-order propagation mode is 150 ?m2 or larger, an effective core area in a second higher-order propagation mode is 180 ?m2 or larger. An effective refractive index in the second higher-order propagation mode is larger than the refractive index of the cladding portion by 0.0002 or more, and an effective refractive index in a third higher-order propagation mode is less than the refractive index of the cladding portion.

Abstract: A method of manufacturing a glass preform is provided. The method including, vaporizing an alkali metal compound or an alkali earth metal compound and being brought the alkali metal compound or the alkali earth metal compound into contact with a hydroxyl group on a surface of porous silica glass and dehydrating the porous silica glass, and sintering the dehydrated porous silica glass and forming a transparent glass body.

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: The present invention relates to a GI-type multi-mode optical fiber in which the outer diameter 2a of a core is 47.5 to 52.5 ?m or 60 to 65 ?m. In the multi-mode optical fiber, stress in the optical axis direction remaining in an outermost peripheral portion of the cladding is tensile stress of 0 to 25 MPa, the outermost peripheral portion of the cladding being defined as a region having a diameter of 1.8b or more when the diameter of the cladding is 2b.

Abstract: An optical fiber (1) includes (i) an inner core (111) whose refractive index distribution has an a profile, (ii) an outer core (112) which surrounds the inner core (111), and (iii) a clad (12) which surrounds the outer core (112). In the optical fiber (1), Rd is set to not less than 0.15, where Rd is a ratio of a refractive index difference between the outer core (112) and the clad (12) to a refractive index difference between a center part of the inner core (111) and the clad (12).

Abstract: A long haul optical fiber transmission system includes a transmitter having a modulated bit rate of at least 40 Gb/s. A receiver is optically coupled to the transmitter with a composite optical fiber span. The optical fiber includes a first optical fiber coupled to the transmitter and a second optical fiber coupled to the first optical fiber. The first optical fiber has an effective area of at least 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L1 from about 30 km to about 90 km. The second optical fiber has an effective area of less than 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L2. The sum of L1 and L2 is at least 160 km. The composite optical fiber span does not include a repeater along the length of the span between the transmitter and the receiver or any rare earth dopants.

Abstract: An excellent optical waveguide forming epoxy resin composition is provided, comprising: (A) a liquid epoxy resin; (B) a solid resin; and (C) a photoacid generator; wherein the liquid epoxy resin (A) comprises a liquid epoxy resin represented by the following general formula (1) as a major component thereof in a proportion of 50 to 80 wt % based on an overall amount of a resin component of the resin composition: wherein R1 and R2 are each a hydrogen atom or a methyl group; R3 to R6 are each a hydrogen atom, a methyl group, a chlorine atom or a bromine atom; X is a C2 to C15 alkylene group, an ethyleneoxy group, a di(ethyleneoxy) group, a tri(ethyleneoxy) group, a propyleneoxy group, a propyleneoxypropyl group, a di(propyleneoxy) propyl group or a tri(propyleneoxy)propyl group; and n is a natural number and has an average value of 1.2 to 5.

Abstract: An optical fiber includes a core (1a) having an oblong rectangular or square cross section and made of quartz, a cladding (2) surrounding the core (1a), having a circular outer cross-sectional shape, having a lower refractive index than the core (1a), and made of resin, and a support layer (3) surrounding the cladding (2) and made of quartz.

Abstract: An optical fiber for use with a light source is illustrated. The optical fiber includes a main body with a cylindrical lateral surface and an end. The end includes an end surface substantially perpendicular to an axis of the main body and a convex connecting surface between the lateral surface and the end surface, thereby increasing incident angles of the light rays that refracted into the main body through the connecting surface.

Abstract: According to some embodiments, the optical fiber comprises: (i) a core having a first index of refraction n1; (ii) a cladding surrounding the core and having a second index of refraction n2, such that n1>n2, wherein cladding has at two sets of stress rods extending longitudinally through the length of the optical fiber, wherein the two sets of stress rods have CTE coefficients and/or softening points different from one another and different from that of cladding.

Abstract: A random array of holes is created in an optical fiber by gas generated during fiber drawing. The gas forms bubbles which are drawn into long, microscopic holes. The gas is created by a gas generating material such as silicon nitride. Silicon nitride oxidizes to produce nitrogen oxides when heated. The gas generating material can alternatively be silicon carbide or other nitrides or carbides. The random holes can provide cladding for optical confinement when located around a fiber core. The random holes can also be present in the fiber core. The fibers can be made of silica. The present random hole fibers are particularly useful as pressure sensors since they experience a large wavelength dependant increase in optical loss when pressure or force is applied.

Abstract: The present invention relates to: a resin composition for forming an optical waveguide, containing (A) a polymer having a hydroxyl group and/or a carboxyl group, (B) a (meth)acrylate having a urethane bond, (C) a polyfunctional blocked isocyanate compound, and (D) a radical polymerization initiator; a resin film for forming an optical waveguide, containing the resin composition for forming an optical waveguide; and an optical waveguide containing a lower cladding layer, a core part and an upper cladding layer, at least one of which contains the resin composition for forming an optical waveguide or the resin film for forming an optical waveguide.

Abstract: Systems and devices enabling a highly compact design for a fiber-based lasing and/or amplifying system are disclosed. In some instances, a tightly-coiled active optical fiber may be coupled with a seed source and a pump source for optical amplification and other applications. Such systems can be disposed in a small footprint package such as a butterfly package or a high heat load package. In some instances, the tightly-wound active optical fiber may further include a fiber Bragg grating adapted to accommodate bends in the active optical fiber. The active optical fiber may further utilize a cladding shaped to maintain an orientation of the active optical fiber in relation to a bend in the fiber.

Abstract: A solid photonic band gap fiber includes: a core area located at a central portion of a cross-section with respect to a longitudinal direction of the fiber, the core area being formed of a solid substance having a low refractive index; cladding areas having base portions formed of a solid substance having a low refractive index, the cladding areas surrounding the core area; and a plurality of fine high refractive index scatterers provided in the cladding areas, and disposed in a dispersed manner so as to surround the core area, the number of fine high refractive index scatterers being formed of a solid substance having a high refractive index, wherein in a state that the solid photonic band gap fiber is held at a predetermined bending radius, propagation in a high-order mode is suppressed by using a difference in a bending loss between a fundamental mode and the high-order mode, and only the fundamental mode is substantially propagated, the fundamental mode and the high-order mode being caused by bending.

Abstract: An embodiment of an apparatus includes an optical fiber for which a complete orthogonal basis of propagating modes at an optical telecommunication frequency includes ones of the propagating modes with different angular momenta. The optical fiber has a tubular optical core and an outer optical cladding in contact with and surrounding the tubular optical core. The tubular optical core has a larger refractive index than the optical cladding. The tubular optical core is configured such that those of the propagating modes whose angular momenta have the lowest magnitude for the propagating modes have substantially the same radial intensity profile.

Abstract: A method for fabricating waveguides comprising nano-apertures for illumination of sub-resolution exposures is presented. In particular, the end of a waveguide, such as an optical fiber, is coated with a material, such as an electrically conducting metal or a semiconductor. This material is then selectively removed through the process of ion milling, creating an aperture in the material at the end of the waveguide. Under normal conditions, if the aperture is smaller than the wavelength of light in the waveguide, there is little or no transmission through the aperture. However, with the appropriate selection of materials and aperture geometry, for example a metallic conducting coating and sub-wavelength “C-shaped” or “bow-tie” aperture, enhancement of transmission of light through the aperture can be achieved, allowing effective illumination of sub-resolution spots using the ion-milled aperture. This can be used in a nanolithography system incorporating waveguide illuminators as well.

Abstract: An amplifying optical fiber includes a core containing oxides of elements selected from the group consisting of silicon, germanium, phosphorus, bismuth, aluminum, gallium with a concentration of bismuth oxide of 10-4-5 mol %, a total concentration of silicon and germanium oxides of 70-99.8999 mol %, a total concentration of aluminum and gallium oxides of 0.1-20 mol % wherein both aluminum and gallium oxide are present and a ratio of aluminum oxide to gallium oxide is at least two, and a concentration of phosphorus oxide from 0 to 10 mol %, and provides a maximum optical gain at least 10 times greater than the nonresonant loss factor in the optical fiber. An outside oxide glass cladding comprises fused silica. The core has an absorption band in the 1000 nm region, pumping to which region provides an increased efficiency of power conversion of pump light into luminescence light in the 1000-1700 nm range.

Abstract: Field-flattening strands may be added to and arbitrarily positioned within a field-flattening shell to create a waveguide that supports a patterned, flattened mode. Patterning does not alter the effective index or flattened nature of the mode, but does alter the characteristics of other modes. Compared to a telecom fiber, a hexagonal pattern of strands allows for a three-fold increase in the flattened mode's area without reducing the separation between its effective index and that of its bend-coupled mode. Hexagonal strand and shell elements prove to be a reasonable approximation, and, thus, to be of practical benefit vis-à-vis fabrication, to those of circular cross section. Patterned flattened modes offer a new and valuable path to power scaling.

Abstract: An apparatus includes an optical fiber having a plurality of optical cores therein. Each optical core is located lateral in the optical fiber to the remaining one or more optical cores and is able to support a number of propagating optical modes at telecommunications wavelengths. Each number is less than seventy.

Abstract: An optical fiber containing an alkali metal element and exhibiting low attenuation as well as excellent radiation resistance is provided. The optical fiber of the present invention has a core region and a cladding region enclosing the core region. The core region contains alkali metal elements by an average concentration of 0.2 atomic ppm or more. The attenuation at a wavelength of 1550 nm after irradiating with the radiation of 0.10 Gy or more of cumulative absorbed dose increases by 0.02 dB/km or less as compared with the attenuation exhibited prior to radiation exposure.

Abstract: A side-hole optical cane for measuring pressure and/or temperature is disclosed. The side-hole cane has a light guiding core containing a sensor and a cladding containing symmetrical side-holes extending substantially parallel to the core. The side-holes cause an asymmetric stress across the core of the sensor creating a birefringent sensor. The sensor, preferably a Bragg grating, reflects a first and second wavelength each associated with orthogonal polarization vectors, wherein the degree of separation between the two is proportional to the pressure exerted on the core. The side-hole cane structure self-compensates and is insensitive to temperature variations when used as a pressure sensor, because temperature induces an equal shift in both the first and second wavelengths. Furthermore, the magnitude of these shifts can be monitored to deduce temperature, hence providing the side-hole cane additional temperature sensing capability that is unaffected by pressure.

Abstract: A gas turbine engine system comprising, a gas turbine engine including a combustion area, a laser, a fuel nozzle including an optical fiber operative to transmit light emitted from the laser to the combustion area, the optical fiber also transmitting a fuel into the combustion area, wherein the light is operative to ignite the fuel in the combustion area.

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: An optical waveguide structure containing a plurality of core portions for transmitting light (L), in which adjacent core portions are arranged with substantially parallel central axes, and the optical paths of the light (L) that is transmitted through the adjacent core portions are in opposite directions, wherein each core portion has a tapered section in which the area of the cross-section in a direction substantially perpendicular to the central axis decreases gradually in the direction of the optical path of the light (L). A highly reliable electronic device containing the optical waveguide structure is also provided.

Abstract: According to some embodiments the optical fiber comprises: (i) a glass core doped with greater than 300 ppm of Er2O3 and at least 0.5 wt % of Al2O3, with a radius R1 from about 3 ?m to about 15 ?m, a relative refractive index delta ?1 from about between 0.3% to 2% relative to the glass cladding; an effective area of LP01 mode between 20 ?m2 and 250 ?m2 at 1550 nm, the glass core radius R1 and refractive index are selected such that the core is capable of supporting the propagation and transmission of an optical signal with X number of LP modes at a wavelength of 1550 nm, wherein X is an integer greater than 1 and not greater than 20; and (ii) a glass cladding surrounding and in direct contact with the glass core.

Abstract: An optical fiber having increased mechanical strength is provided. The optical fiber includes an over cladding layer that has a compressive stress of at least 100 MPa.