Abstract: Disclosed is an improved, single-mode optical fiber possessing 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: A buffered optical fiber arrangement that includes a buffer tube in which is provided optical fibers and a texturized yarn coated with a water-swellable material. The filament diameter of the yarn used in the present invention may be between about 5 microns and about 100 microns, more preferably between about 10 and about 60 microns, still more preferably between about 20 and about 40 microns. The linear density, or denier in grams per 9000 meters, of the base yarn may be between about 100 and 1000, more preferably between about 200 and 600, or still more preferably between about 250 and 350. The degree of decrease in length (the “degree of texturizing”) between the perfectly straight filaments before texturizing and the texturized filament may be between 1 percent and 90 percent, more preferably between about 2 percent and 50 percent, or still more preferably between about 5 percent and 25 percent.

Abstract: An optical fiber that is relatively insensitive to bend loss and alleviates the problem of catastrophic bend loss comprises a core region and a cladding region configured to support and guide the propagation of light in a fundamental transverse mode. The cladding region includes (i) an outer cladding region, (ii) an annular pedestal (or ring) region, (iii) an annular inner trench region, and (iv) an annular outer trench region. The pedestal region and the outer cladding region each have a refractive index relatively close to that of the outer cladding region. In order to suppress HOMs the pedestal region is configured to resonantly couple at least one (unwanted) transverse mode of the core region (other than the fundamental mode) to at least one transverse mode of the pedestal region. In a preferred embodiment, the fiber is configured so that, at a signal wavelength of approximately 1550 nm, its bend loss is no more than about 0.1 dB/turn at bend radius of 5 mm and is no more than about 0.

Abstract: The present disclosure relates to a telecommunications cable having a layer constructed to resist post-extrusion shrinkage. The layer includes a plurality of discrete shrinkage-reduction members embedded within a base material. The shrinkage-reduction members can be made of a liquid crystal polymer. The disclosure also relates to a method for manufacturing telecommunications cables having layers adapted to resist post-extrusion shrinkage.

Abstract: In an optical touch panel 20 using optical waveguides, a pigment mixture consists of at least 2 kinds of pigments is contained in a clad 14. The pigment mixture has stronger absorption of light in a visible range than in a near-infrared range. Signal beams in the near-infrared range are hardly absorbed, although ambient light having entered the clad 14 in the visible range is strongly absorbed. This makes it possible to significantly reduce ambient light in the visible range to enter cores 12 after passing through the clad 14 and it is possible to use the optical touch panel 20 outdoors, either.

Abstract: A core glass and a fiber-optic light guide made from it and a cladding glass are described. The core glass is in the alkali-zinc-silicate system and contains, in Mol % on an oxide basis: 54.5-65, SiO2; 18.5-30, ZnO; 8-20, ? alkali metal oxides; 0.5-3, La2O3; 2-5, ZrO2; 0.02-5, HfO2; 2.02-5, ? ZrO2+HfO2; 0.4-6, BaO; 0-6, SrO; 0-2, MgO; 0-2, CaO; 0.4-6, ? alkaline earth metal oxides; 0.5-3, Li2O, but no more Li2O than 25% of the ? alkali metal oxides; >58.5, ? SiO2+ZrO2+HfO2. A molar ratio of Na2O/K2O is from 1/1.1 to 1/0.3. A molar ratio of ZnO to BaO is greater than 3.5.

Abstract: A plastic optical fiber cable includes: a bare optical fiber including a core made of a poly(methyl methacrylate) or a copolymer including methyl methacrylate as a major component and a cladding layer including, at least in the outermost layer, a layer made of a certain fluorine-containing olefin-based resin; and a coating layer provided on the outer surface thereof. The coating layer includes a protective coating layer, a light blocking coating layer, and a functional coating layer, the layers being provided in the order mentioned from inner side. The protective coating layer is made of a certain resin material. The light blocking coating layer is made of a nylon-based resin including, as a major component, nylon 11 or nylon 12, the nylon-based resin containing monomer and oligomer compounds derived from the nylon-based resin in an amount of a certain range.

Abstract: An apparatus includes a waveguide having a core layer and first and second cladding layers on opposite sides of the core layer, wherein the cladding layers comprise a binary oxide composition. In another example, the cladding layers include a ternary or quaternary combination of oxides and/or oxynitrides. In another example, the cladding layers include a silicon oxynitride.

Abstract: The viewing angle dependence of the ? characteristic in a CPA mode liquid crystal display device is reduced in a desired direction. The liquid crystal display device is usable for a use in which a viewing angle characteristic in direction D1 parallel to a display plane needs to be higher than a viewing angle characteristic in another direction D2 parallel to the display plane. An electrode of the liquid crystal display device includes a solid area formed of a conductive film and a non-solid area with no conductive film. The solid area of the electrode includes a plurality of unit solid areas, above each of which a liquid crystal domain exhibiting a radially inclined orientation state is formed.

Abstract: An optical fiber includes a glass fiber having a glass core and a cladding which contains voids spaced apart from the core. The voids act as trapping sites for ingressing molecules from the surrounding environment, thereby reducing the effect of such molecules on the fiber's light-transmission properties.

Abstract: An electro-optical memory cell having a non-volatile programmable refractive index and a method of making. The memory cell includes: a waveguiding structure having a transition metal oxide with oxygen vacancies; a plurality of electrodes for applying an electrical field; and an optical detector for detecting a state of the memory cell. The method includes: fabricating a waveguiding structure having a transition metal oxide with oxygen vacancies; positioning a plurality of electrodes for application of an electric field; arranging the transition metal oxide and the electrodes such that when an electric field is applied, the oxygen vacancies migrate in a direction that has a component which is radial relative to a center of the beam path; applying the electric field thereby programming the refractive index to set a state of the memory cell; and detecting the state of the memory cell using an optical detector.

Abstract: The present invention relates to an optical fiber which has a structure for further increasing an FOM (=|dispersion|/loss) and which can be applied to a dispersion compensation module. The optical fiber is mainly composed of silica glass and has a core region including a center of an optical axis, a depressed region surrounding the core region, a ring region surrounding the depressed region, and a cladding region surrounding the ring region and doped with F. As compared with the refractive index of pure silica glass, a relative refractive index difference of the core region is greater than 2% but less than 3%, a relative refractive index difference of the depressed region is ?1% or more but ?0.5% or less, a relative refractive index difference of the ring region is 0.01% or more but 0.24% or less, and a relative refractive index difference of the cladding region is ?0.3% or more but ?0.1% or less. The FOM at the wavelength of 1550 nm is 250 ps/nm/dB or more.

Abstract: The present disclosure relates to a telecommunications cable having a layer constructed to resist post-extrusion shrinkage. The layer includes a plurality of discrete shrinkage-reduction members embedded within a base material. The shrinkage-reduction members can be made of a liquid crystal polymer. The disclosure also relates to a method for manufacturing telecommunications cables having layers adapted to resist post-extrusion shrinkage.

Abstract: There is provided an evanescent wave multimode optical waveguide sensitive to a chemical species or to a physical parameter. The optical waveguide comprises a core and a cladding having a cladding refractive index lower than that of the core for guiding light to be propagated in the optical waveguide. The cladding defines with the core an optical waveguide providing mode coupling. A chemical indicator is provided in the cladding for causing a variation of the optical absorption of the cladding as a function of the chemical species or the physical parameter. The cladding is interrogated by the evanescent wave of the propagated light. The mode coupling causes unabsorbed light power to be redistributed among the multiple modes while light propagates along the optical waveguide.

Abstract: The invention relates to an optical fibre comprising a gain medium which is equipped with: a core (22) which is formed from a transparent material and nanoparticles (24) comprising a doping element and at least one element for enhancing the use of said doping element; and an outer cladding (26) which surrounds the core. The invention is characterised in that the doping element is erbium (Er) and in that the enhancing element is selected from among antimony (Sb), bismuth (Bi) and a combination of antimony (Sb) and bismuth (Bi). According to the invention, one such fibre is characterised in that the size of the nanoparticles is variable and is between 1 and 500 nanometres inclusive, and preferably greater than 20 nm.

Abstract: A novel polyimide compound which has a lower linear expansion coefficient and permits film formation by a spin coating method or the like, a preparation method for the polyimide compound, and an optical film and an optical waveguide produced by employing the compound. The polyimide compound has a structural unit represented by the following general formula (1): wherein X and Y are each a covalent single bond, —CO—, —O—, —CH2—, —C(CF3)2— or —CR(R?)— (wherein R and R?, which may be the same or different, are each a linear or branched C1 to C4 alkyl group); A and B are each a halogen group; a and b, which are the numbers of the groups A and B, respectively, are each 0 or an integer of 1 or 2; and R1, R2, R3 and R4, which may be the same or different, are each a hydrogen atom or a linear C1 to C4 alkyl group.

Abstract: A novel polyimide compound which has a low linear expansion coefficient and permits film formation by a spin coating method or the like, a preparation method for the polyimide compound, and an optical film and an optical waveguide produced by employing the compound. The polyimide compound has a structural unit represented by the following general formula (1): wherein X is a covalent single bond, —CH2—, —C(CF3)2— or —CR(R?)— (wherein R and R?, which may be the same or different, are each a C1 to C6 alkyl group or an aryl group); A and B, which may be the same or different, are substituents each selected from a hydroxyl group, a halogen group and a C1 to C4 alkyl group; a and b, which are the numbers of the substituents A and B, respectively, are each an integer of 0 to 2; and o, p and q are each an integer of 1 to 5.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: Disclosed is an optical fiber having a silica-based core comprising an alkali metal oxide a silica-based core, said core comprising an alkali metal oxide selected from the group consisting of K2O, Na2O, Li2O, Rb2O, Cs2O and mixtures thereof in an average concentration in said core between about 10 and 10000 ppm by weight, and a silica-based cladding surrounding and directly adjacent the core, the cladding including a region having a lower index of refraction than the remainder of such cladding. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained which exhibits a cable cutoff less than 1400 nm chromatic dispersion at 1550 nm between about 13 and 19 ps/nm/km, and a zero dispersion wavelength less than about 1324 nm.

Abstract: Apparatus and method for distributed absorption of pump light over a length of delivery fiber that is, for example in some embodiments, fusion spliced to an end of a multiply clad gain fiber that has significant unused pump light at the end of the gain fiber. In some embodiments, this includes coupling a fiber amplifier to a passive-core delivery fiber that includes a distributed pump dump. In some embodiments, at an output end of the amplifying fiber there is still a significant amount of pump power. If all this pump power is dumped in one small place (e.g., at a splice between the amplifying fiber and a passive delivery fiber) a hot spot will result, leading to unreliable devices that fail (have catastrophic changes in operating performance). The present invention provides a distributed pump dump built into a delivery fiber that is passive to the signal in its core.

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

Abstract: Planar waveguides having quantum dots and methods of manufacture of the planar waveguide are described.

Abstract: The present invention relates to a resin composition for an optical waveguide comprising (A) a photopolymerizable monomer, (B) a binder polymer and (C) a photoinitiator, wherein the photopolymerizable monomer (A) contains a hydroxyl group-containing fluorinated mono(meth)acrylate base compound. Provided are a resin composition for an optical waveguide which has a high transparency in a wavelength of 1.3 ?m and which is excellent in formation of a thick film and an adhesive property and an optical waveguide prepared by using the same.

Abstract: An electro-optic waveguide device comprising an electro-optic polymer core and at least one crosslinked polymer clad, wherein the crosslinked polymer clad is comprised of a first constitutional unit derived from a compound having the formula wherein, m=0-6; n=0-1; q=1-3; y=0-3; Ar1 is an aryl or heteroaryl group; and independently at each occurrence p=0-1; R is an alkyl, heteroalkyl, aryl, or heteroaryl group; Ar2 is an aryl or heteroaryl group; and X is a crosslinkable group. The R group may be an alkyl or heteroalkyl group with at least 6 atoms in a straight chain. In some embodiments, the R group is an alkoxy capped oligoalkylene group. Other embodiments include a polymer comprising a first constitutional unit derived from a compound having the formula described above.

Abstract: The microstructured optical fibre comprises a core (4) surrounded by a sheath (1) comprising a base material having a refraction index (ni) and a plurality of at least two different types of inclusion: a first type of inclusion (2) having a refraction index n2 (n2>n1), and a second type of inclusion (3) having a refraction index n3 (n3<n1). The inclusions (2, 3) are arranged and dimensioned in such a way as to ensure guidance, by total internal reflection (RTI), of a fundamental mode of the light, centred on a wavelength ?RTI, and of a fundamental mode of the light in the first photonic forbidden band (BG1), centred on a wavelength ?BG1, which is different to that ?RTI of the fundamental mode guided by total internal reflection (RTI).

Abstract: A core region is doped with an impurity. A first cladding region is formed in a layered structure around the core region, including a microstructure. A second cladding region is formed in a layered structure around the first cladding region, including a homogeneous material. A relative refractive-index difference ?1 between the core region and the second cladding region is equal to or more than 0.4% and equal to or less than 1.0%.

Abstract: Disclosed is a method of producing a planar multimode optical waveguide by direct photo-patterning and, more particularly, to an optical waveguide material and a method of producing the same. It is possible to control the refractive index of the optical waveguide, and the optical waveguide has a desirable refractive index distribution throughout different dielectric regions. In the method, it is unnecessary to conduct processes of forming a clad layer and of etching a core layer, thus a production process is simplified. The method comprises coating a photosensitive hybrid material having a refractive index or a volume changed by light radiation, in a thickness of 10 microns or more, and radiating light having a predetermined wavelength onto the coated photosensitive hybrid material to form the multimode optical waveguide due to a change in refractive index of a portion onto which light is radiated.

Abstract: An electro-optical device having a non-volatile programmable refractive index. The device includes: a waveguiding structure with waveguiding material, the waveguiding structure defining an optical beam path, where the waveguiding structure includes a transition metal oxide with oxygen vacancies that migrate when exposed to an electric field; and a plurality of electrodes for applying an electric field to a region including the transition metal oxide with oxygen vacancies; where the transition metal oxide and the electrodes are arranged such that under the applied electric field the oxygen vacancies migrate in a direction that has a component which is radial relative to a center of the beam path. Further, there is provided a method for making the electro-optical device, including: fabricating the waveguiding structure; positioning a plurality of electrodes for application of an electric field; and arranging the transition metal oxide and the electrodes.

Abstract: The present invention provides a rare earth element-doped optical fiber amplifier having a function which allows to omit an optical isolator component, and a method for providing the optical non-reciprocity using the same. In the optical fiber, the optical fiber matrix material is a ferroelectric solid state material, and the ferroelectric solid state material is doped by a rare earth element such as erbium (Er) or thulium (Tm). The optical fiber is characterized by an optical amplification function and an optical non-reciprocity function.

Abstract: An optical fiber in which the macro-bending loss is lowered while an MFD is maintained large, and a waveguide including the optical fiber. The optical fiber includes a core region doped with an impurity; a first cladding region formed as a layer around the core region and including holes as microstructures; and a second cladding region formed as a layer around the first cladding region and made of a homogeneous material. A relative refractive-index difference ?1 between the core region and the second cladding region is equal to or higher than 0.01% and lower than 0.3%. A total cross-sectional area of the holes in the first cladding region with respect to a total cross-sectional area of the core region, the first cladding region, and the second cladding region is equal to or smaller than 20%. A waveguide is formed using the optical fiber.

Abstract: An optical fiber that includes a core containing a first concentration of germanium, an inner cladding arranged on the core, the inner cladding containing a second concentration of germanium and having a first diffusion coefficient, and an outer cladding arranged on the inner cladding, the outer cladding having a second diffusion coefficient, where the first diffusion coefficient is larger than the second diffusion coefficient, and where the first concentration of germanium is about 200% or more of the second concentration of germanium. An optical fiber constructed in this manner can be spliced with an optical fiber having a different MFD, such as a single-mode optical fiber or an erbium-doped optical fiber, with low splice loss and a sufficient splicing strength.

Abstract: An optical fiber, comprising: (i) a core having a core center and a radius or a width a, (ii) a cladding surrounding the core, and (iii) at least one stress member situated proximate to the fiber core within the cladding, said stress member comprising silica co-doped with F and at least one dopant selected from the list consisting of: GeO2, P2O5, Y2O3, TiO2 and Al2O3, wherein distance b between the stress member and the core center satisfies the following equation: 1?b/a<2.

Abstract: Provided are polymers comprising the condensation product of silicon-containing reactants. Also provided are compositions suitable for use in forming optical waveguides which include such polymers, as well as optical waveguides formed from such polymers. The polymers, compositions and optical waveguides have particular use in the formation of printed wiring boards having electrical and optical functionality.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: A single mode optical transmission fiber comprises a depressed core having at least 0.41 weight percent fluorine and an index difference (|?n1|) with pure silica greater than 1.5×10?3, a depressed cladding having at least 1.2 weight percent fluorine and an index difference (|?n2|) with pure silica greater than 4.5×10?3 and an index difference (|?n2|?|?n1|) with the depressed core greater than or equal to 3×10?3.

Abstract: According to one example of the invention an optical fiber comprises: (i) a silica based core, said core having a core diameter greater than 80 ?m and a numerical aperture NA?0.24; and (ii) a silica based cladding in contact with and surrounding the core and having a second index of refraction n2, such that n1>n2; wherein the cladding includes B and F. Preferably the numerical aperture NA is at least 0.3.

Abstract: Disclosed are fiber optic cable assemblies having a composite covering disposed about a portion of a transition location for providing a fiber optic assembly suitable for indoor or indoor/outdoor applications. The composite covering provides a combination of an underlying heat dissipative structure, such as a metal foil along with a high temperature capable substrate, such as mica, thereby providing the desired characteristics for indoor or indoor/outdoor use that a single layer of either material is incapable of providing. The covering may also include an optional flame-retardant wrap as an outer portion for sealing and/or mechanical protection.

Abstract: An optical fiber comprising a flame retardant UV light-curable tight-buffer coating coated onto the fiber, wherein said tight-buffer coating is substantially halogen-free, and has a limiting oxygen index of at least about 22%, and wherein said tight-buffer coating is removable from said fiber with a strip-force of less than about 1800 grams when the fiber is upjacketed with said coating at a line speed of at least 300 m/min.

Abstract: Methods of fabricating optical elements that are encapsulated in monolithic matrices. The present invention is based, at least in one aspect, upon the concept of using multiphoton, multi-step photocuring to fabricate encapsulated optical element(s) within a body of a photopolymerizable composition. Imagewise, multiphoton polymerization techniques are used to form the optical element. The body surrounding the optical element is also photohardened by blanket irradiation and/or thermal curing to help form an encapsulating structure. In addition, the composition also incorporates one or more other, non-diffusing binder components that may be thermosetting or thermoplastic. The end result is an encapsulated structure with good hardness, durability, dimensional stability, resilience, and toughness.

Abstract: An optical fiber preform is assembled by inserting core rod segments axially end to end inside of a first glass overclad tube having a first, relatively low concentration of a given impurity that contributes to signal attenuation in an optical fiber to be drawn from the preform. The first overclad tube with the contained core rod segments are inserted in a second glass tube having a second concentration of the given impurity which is higher than the first concentration. The wall thickness of the first overclad tube is preferably less than that of the second overclad tube, thus reducing the amount of high purity glass needed to form the first overclad tube and attendant manufacturing costs. The core rod segments may include salvageable remnants from a single long core rod produced, for example, by vapor axial deposition (VAD).

Abstract: Disclosed herein is a printed circuit board for an optical waveguide, including a base board, and an optical waveguide formed on the base board. The optical waveguide includes a lower clad layer formed on the base board, an insulation layer formed on the lower clad layer and having a core-forming through-hole, a core part formed on a region of the lower clad layer, which is exposed through the through-hole, and an upper clad layer formed in the through-hole and on the insulation layer.

Abstract: An optical fiber is made of silica-based glass, and includes a core and a cladding. The optical fiber has a mode field diameter of 5.4 micrometers or larger at a wavelength of 1300 nanometers, transmits light with a wavelength of 1250 nanometers in a single mode, and has a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nanometers when the optical fiber is bent with a curvature radius of 1 millimeter.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding. The optical fiber having a mode field diameter of 6.5 ?m or larger at a wavelength of 1300 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nm when the optical fiber is bent with a curvature radius of 1.5 mm.

Abstract: The present disclosure relates to a telecommunications cable having a layer constructed to resist post-extrusion shrinkage. The layer includes a plurality of discrete shrinkage-reduction members embedded within a base material. The shrinkage-reduction members can be made of a liquid crystal polymer. The disclosure also relates to a method for manufacturing telecommunications cables having layers adapted to resist post-extrusion shrinkage.

Abstract: There are provided an optical fiber ribbon and optical fiber cable which suppress the deterioration of polarization mode dispersion and contribute to the increase of communication capacity in wavelength division multiplexing. An optical fiber ribbon includes a plurality of optical fibers 12 tied in a bundle and a ribbon coating layer 13 formed around the plurality of optical fibers to integrate the plurality of optical fibers, wherein the glass-transition temperature of the coating ranges from 80° C. to 130° C. and “a” is 0.01 mm2 or less, where “a” is a sectional area of the ribbon coating layer 13 in a cross section in which outer half of the optical fiber at an edge of the ribbon and the coating of the optical fiber ribbon are taken along a line passing the center of the glass optical fiber positioned at one of edges of the ribbon out of the plurality of the optical fibers and being perpendicular to the horizontal plane of the optical fiber ribbon.

Abstract: In a waveguide 10 including a substrate 1, a lower clad 2, an upper clad 3, and a core 4, the outline of a cross section perpendicular to the light propagating direction of the core 4 surrounded by the lower clad 2 has a shape curved with respect to the center of the cross section. The separation in the waveguide is thereby prevented, and the reliability of the optical property is enhanced.

Abstract: The invention relates to vitreous compositions, in particular of the vitroceramic type, transparent to infrared, production and uses thereof. Said compositions comprise in mol. %: Ge 5-40, Ga<1, S+Se 40-85, Sb+As 4-40, MX 2-25, Ln 0-6, adjuncts 0-30, where M=at least one alkaline metal, selected from Rb, Cs, Na, K and Zn, X=at least one atom of chlorine, bromine or iodine, Ln=at least one rare earth and adjunct=at least one additive comprising at least one metal and/or at least one metal salt with the sum of all molar percentages of the components present in said composition being 100.

Abstract: An apparatus in one example has: a fiber having a representative refractive index profile, the refractive index profile having at least a core and a pedestal; and the fiber having a modal index in the core that is greater than a modal index of the pedestal at a predetermined signal wavelength. The fiber may also have a cladding, and may have a significantly increased index of refraction over a cladding material of the cladding to reduce effects of Stimulated Raman Scattering.

Abstract: A single mode optical transmission fiber comprises a depressed core having at least 0.41 weight percent fluorine and an index difference (|?n1|) with pure silica greater than 1.5×10?3, a depressed cladding having at least 1.2 weight percent fluorine and an index difference (|?n2|) with pure silica greater than 4.5×10?3 and an index difference (|?n2|?|?n1|) with the depressed core greater than or equal to 3×10?3.

Abstract: An optical amplifier including an optical waveguide layer (for example channel-shaped optical waveguide layer) including Pb1?xLax(ZryTi1?y)1?x/4O3(PLZT: 0<x<0.3, 0<y<1.0) doped with a rare earth element at an amount of 0.2 mol % to 11.0 mol %, the optical waveguide layer (for example channel-shaped optical waveguide layer) being formed as a single crystal film by solid-phase epitaxial growth.