Abstract: The present invention relates to an optical communications system that allows improving OSNR while suppressing the power increase of pumping light for distributed Raman amplification. In the optical communications system, an optical fiber is laid in a transmission section between a transmitter station (or repeater station) and a receiver station (or repeater station), and optical signals are transmitted from the transmitter station to the receiver station via the optical fiber. In the optical communications system, pumping light for Raman amplification, outputted by a pumping light source provided in the receiver station, is fed into the optical fiber via an optical coupler, and the optical signals are distributed-Raman-amplified in the optical fiber. The transmission loss and the effective area of the optical fiber satisfy, at the wavelength of 1550 nm, a predetermined relationship.

Abstract: A single-mode optical fiber includes a central core, an intermediate cladding, a depressed trench, and an external optical cladding. The central core has a radius r1 and a positive refractive index difference ?n1 with the optical cladding. The intermediate cladding has a radius r2 and a positive refractive index difference ?n2 with the optical cladding, wherein ?n2 is less than ?n1. The depressed trench has a radius r3 and a negative index difference ?n3 with the optical cladding. At a wavelength of 1310 nanometers, the optical fiber has a mode field diameter (MFD) between 8.6 microns and 9.5 microns and, at a wavelength of 1550 nanometers, the optical fiber has bending losses less than about 0.25×10?3 dB/turn for a radius of curvature of 15 millimeters. At a wavelength of 1260 nanometers, attenuation of the LP11 mode to 19.3 dB is achieved over less than 90 meters of fiber.

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 ncof the core portion. Methods of forming the photodarkening resistant optical fiber lasing media are also disclosed.

Abstract: The invention relates to an optical fiber as an optical waveguide for the single-mode operation. The present invention proposes a fiber having a microstructure, by which the propagation of modes of a higher order are selectively suppressed in the optical waveguide. At the same time, the propagation of transversal modes of a higher order is dampened more strongly than the propagation of the fundamental modes of the optical waveguide.

Abstract: An optical fiber apparatus having a wavelength of operation comprises an optical fiber comprising a core; a pump cladding disposed about the core for receiving pump optical energy having a pump wavelength; and a second cladding disposed about for tending to confine pump optical energy to the pump cladding. The core can comprise a rare earth material for providing optical energy having the wavelength of operation responsive to the optical fiber receiving the pump optical energy, and the fiber can further comprise at least one ring core spaced from the core, the ring core defined by inner and outer diameters and comprising the cross sectional area therebetween. The ring core can comprise an absorbing material for absorbing optical energy having the wavelength of operation.

Abstract: A light-illuminating probe with increased spatial spread of an external illumination light and a fundus observing apparatus, a fundus surgery apparatus, and an endoscope using the light-illuminating probe are provided. The light-illuminating probe includes a light-transmitting portion which is constructed with at least a first dielectric material having a light transparency and a light-radiating portion which is constructed with a second dielectric material having a light transparency to be formed in an extension portion of the light-transmitting portion.

Abstract: The invention relates to an optical fiber, in particular a laser fiber, containing a doped glass fiber core (1) and cladding (2) around the latter with a refraction index profile which decreases outwards from the fiber core. The optical fiber is distinguished by at least one intermediate layer (3, 4, 5) being disposed between the glass fiber core and the cladding to reduce the mechanical tension therebetween. In one advantageous embodiment, the intermediate layer is doped in such a way as to ensure a stepped mechanical tension distribution between the glass fiber core and the cladding, and is co-doped in such a way as to reduce the refractive index and counteract the refraction index-increasing effect of the intermediate layer doping.

Abstract: A microstructured optical fiber for transmitting optical signals comprised of light, the optical fiber comprising: a core region disposed about a longitudinal centerline and having a refractive index profile with a first refractive index, and a cladding region surrounding the core region, the cladding region comprising an annular void-containing region comprised of non-periodically disposed voids; wherein maximum void diameter in nm is given by Dmax and the maximum void length in cm is not greater than 2.5×105×(dmax)?1.7.

Abstract: A preform for forming a hollow-core, slotted photonic band-gap (PBG) optical fiber for use in an environmental sensor, and methods of forming such a fiber using the preform are disclosed. The preform comprises a slotted cladding tube that surrounds a slotted, hollow-core PBG cane. The slots in the cladding tube and PBG cane are longitudinally formed and substantially aligned with each other. When the preform is drawn, the slots merge to form an elongated side opening or slot in the resulting hollow-core PBG fiber.

Abstract: Provided is an optical fiber including: a core at a center thereof; a first cladding adjacent to the core to cover a circumference of the core; and a second cladding adjacent to the first cladding to cover a circumference of the first cladding, where 0.35%?(?1??2)?0.65%, 0.30%??1?0.55%, ?0.20%??2??0.05%, 0.22?a/b?0.34, and 4?b?|?2|?10 hold, and loss increase resulting when the optical fiber is wound on a mandrel having a diameter of 20 mm is 0.

Abstract: An apparatus includes a waveguide including a core layer having curved edges shaped to reflect light to a focal point, and a grating positioned adjacent to or imbedded in the core layer, wherein at least a portion of the grating is positioned between the curved edges and adjacent to or imbedded in a portion of the core layer that is not traversed by light reflected from the curved edges. A data storage device that includes the apparatus is also provided.

Abstract: The present invention relates to a crystal fiber, and more particularly to a Ti: sapphire crystal fiber, a manufacturing method thereof, and a wide band light source with the same. The Ti: sapphire single crystal is grown by means of laser-heated pedestal growth (LHPG) method into a crystal fiber of a predetermined diameter. The crystal fiber is enclosed by a glass capillary and is grown into a single cladding crystal fiber. The wide band light source comprises: a pumping source for providing a pumping light; a single cladding Ti: sapphire crystal fiber for absorbing the pumping light and emitting the wide band light.

Abstract: The invention provides a means for preparing rare-earth-doped ?-(Al1-xGax)2O3 films by molecular beam epitaxy (MBE). The invention provides a composition of matter, rare-earth-doped ?-(Al1-xGax)2O3 films, and methods to provide thin films of this material. The invention also provides a means to prepare thin film rare-earth-doped ?-(Al1-xGax)2O3, including Nd: ?-(Al1-xGax)2O3, for use in solid state lasers. Rare-earth-doped ?-Ga2O3 and rare-earth-doped alloys of ?-Ga2O3 and ?-Al2O3 with the same single-crystal structure independent of Ga/Al ratio are disclosed herein.

Abstract: The polarization-maintaining fiber of the invention includes a core (1) made of germanium doped silica glass; a stress-applying part (3) made of boron doped silica glass; a cladding (2) made of pure silica glass; and a polyimide coating layer (4) with a thickness of 10 ?m or less that surrounds the outer periphery of the cladding (2).

Abstract: Provided is an optical fiber including: a first core at a center thereof; a second core adjacent to the first core to cover a circumference of the first core; a third core adjacent to the second core to cover a circumference of the second core; and a cladding adjacent to the third core to cover a circumference of the third core, where conditions of 0.28%??1?0.4%, ?0.05%??2?0.05%, ?1.0%??3??0.5%, 3.8 ?m?a?4.5 ?m, 12 ?m?b?21 ?m, and 1.5 ?m?c-b?10 ?m hold, and loss increase resulting when the optical fiber is wound on a mandrel having a diameter of 20 mm is 0.

Abstract: A method for fabricating an optical waveguide includes setting, on a lower cladding of an optical waveguide, a light-reflecting feature and at least one waveguide core distinct from the reflecting feature. An upper cladding is applied that embeds both the light-reflecting feature and the waveguide core.

Abstract: (1) A method for producing a flexible optical waveguide, containing: a step of forming a first cladding layer; a step of forming a first core layer by laminating a resin film for forming a core layer on at least one end portion of the first cladding layer; a step of forming a second core layer by laminating a resin film for forming a core layer on an entire surface of the first core layer and the first cladding layer; a step of forming a core pattern by patterning the first and second core layers; and a step of embedding the core pattern by forming a second cladding layer on the core pattern and the first cladding layer, (2) a flexible optical waveguide containing a lower cladding layer, a core part and an upper cladding layer, the upper cladding layer having a width that is smaller than a width of the lower cladding layer at least in a bent portion, and is equal to or smaller than a width of the lower cladding layer in an end portion, and the lower cladding layer having a width in a bent portion that is equa

Abstract: A fiber optic includes a plurality of fibers each including a core made of core glass for propagating light and a cladding for covering an outer periphery of the core and made of cladding glass lower in refractive index than the core glass and an absorber glass arranged between the plurality of fibers and for absorbing light leaking from the plurality of fibers. The plurality of fibers are bundled and integrated. The absorber glass contains Fe3O4 being iron oxide crystals.

Abstract: A light collecting optical fiber improves light injection efficiency into the optical fiber. The light collecting optical fiber is equipped with a plurality of optical waveguide portions and light collecting portions between the adjacent optical waveguides. The optical waveguide portion includes a core and a cladding layer surrounding the core and constitutes an optical fiber. The light collecting portion is formed in a shape bulging out in radial direction from the optical waveguide portion and is constituted so that it injects external light to the optical waveguide portion.

Abstract: Adverse hydrogen aging limitations in multiply-doped optical fibers are overcome by passivating these optical fibers using a deuterium passivation process. This treatment essentially pre-reacts the glass with deuterium so that the most active glass sites are no longer available to react with hydrogen in service. Optical fibers of main interest are doped with mixtures of germanium and phosphorus. Optimum passivating process conditions are described.

Abstract: An optical fiber connection structure which reduces MPI in the use of an optical fiber with a bend resistance improved by forming holes in the fiber, and a single-mode fiber which reduces MPI are provided. A second cladding portion of a second single-mode fiber 20 includes holes 28, and thus, the second single-mode fiber 20 has low bending loss. A portion of the second single-mode fiber 20 connected to a first single-mode fiber 10a is made solid by filling corresponding portions of the holes 28 over the length L0, and light in a mode LP11 is significantly attenuated in this portion, thereby reducing MPI.

Abstract: A GI type optical fiber of the present invention is a GI type optical fiber having a core component and a cladding component disposed around the outer periphery of the core component, the core component includes a polymer containing at least 55 wt % chlorostyrene monomer and a dopant, and the cladding component includes a polymer of a monomer containing at least 35 wt % methyl methacrylate. It is an object of the present invention to provide a GI type optical fiber in which chlorostyrene is used as the predominant component of the monomer that constitutes the core component, and therefore has excellent transparency and good flexibility, and allows high-speed communication.

Abstract: A stretcher fiber includes a core region, inner trench region, ring region, outer trench region, and outer cladding region. The core region has a radius r1, a refractive index n1, and a positive effective refractive index ?n1 with respect to an outer cladding region having an outer radius r0 and a refractive index n0, where ?n0 is equal to n1?n0. The inner trench region surrounds the core region and has an outer radius r2, a refractive index n2 less than n0, and a negative effective refractive index ?n2 equal to n2?n0. The ring region surrounds the trench region and has an outer radius r3, a refractive index n3 greater than n0, and a positive effective refractive index ?n3 equal to n3?n0. The outer trench region surrounds the ring region and has an outer radius r4, a refractive index n4 less than n0, and a negative effective refractive index ?n4 equal to n4?n0. The outer cladding region surrounds the outer trench region.

Abstract: An analytical assembly within a unified device structure for integration into an analytical system. The analytical assembly is scalable and includes a plurality of analytical devices, each of which includes a reaction cell, an optical sensor, and at least one optical element positioned in optical communication with both the reaction cell and the sensor and which delivers optical signals from the cell to the sensor. Additional elements are optionally integrated into the analytical assembly. Methods for forming and operating the analytical system are also disclosed.

Abstract: Provided is a manufacturing method for an optical fiber preform of which the core is doped with a rare earth element. The method includes: depositing glass particles within a silica tube by the modified chemical vapor deposition method, the glass particles mainly consisting of silicon dioxide; adding the rare earth element and aluminum to the glass particles within the silica tube by the solution doping method; heating the silica tube while flowing a phosphorous-containing gas into the silica tube to sinter the glass particles within the silica tube while adding the phosphorous; and heating and collapsing the silica tube to which the rare earth element, the aluminum, and the phosphorous are added.

Abstract: A composite waveguide includes a central core configured to transmit a plurality of modes and at least one side core helically wound about the central core and configured to be selectively coupled to at least a portion of the plurality of modes in the central core.

Abstract: A superconducting flux digital-to-analog converter includes a superconducting inductor ladder circuit. The ladder circuit includes a plurality of closed superconducting current paths that each includes at least two superconducting inductors coupled in series to form a respective superconducting loop, successively adjacent or neighboring superconducting loops are connected in parallel with each other and share at least one of the superconducting inductors to form a flux divider network. A data signal input structure provides a respective bit of a multiple bit signal to each of the superconducting loops. The data signal input structure may include a set of superconducting quantum interference devices (SQUIDs). The data signal input structure may include a superconducting shift register, for example a single-flux quantum (SFQ) shift register or a flux-based superconducting shift register comprising a number of latching qubits.

Abstract: The invention includes optical signal conduits having rare earth elements incorporated therein. The optical signal conduits can, for example, contain rare earth elements incorporated within a dielectric material matrix. For instance, erbium or cerium can be within silicon nanocrystals dispersed throughout dielectric material of optical signal conduits. The dielectric material can define a path for the optical signal, and can be wrapped in a sheath which aids in keeping the optical signal along the path. The sheath can include any suitable barrier material, and can, for example, contain one or more metallic materials. The invention also includes methods of forming optical signal conduits, with some of such methods being methods in which the optical signal conduits are formed to be part of semiconductor constructions.

Abstract: An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core. The optical fiber includes a defect substantially surrounded by the cladding, the defect increasing a coupling coefficient between the first core and the second core.

Abstract: A multi-core holey fiber with suppression of crosstalk deterioration among transmitted optical signals in a plurality of cores, and an optical transmission system using the fiber are disclosed. The multi-core holey fiber comprises a plurality of cores arranged separately from each other, and a cladding surrounding the plurality of cores wherein the cladding has plurality of holes arranged in a triangular lattice shape to create hole layers around the plurality of cores. Additionally, d/? is not more than 0.5, where ? [?m] is lattice constant of the triangular lattice, d [?m] is diameter of each of the holes; a distance between adjacent cores is equivalent to not less than six hole layers; the cores arranged farthest from the center of the multi-core holey fiber is surrounded by not less three hole layers; and the sum of the coupling coefficients between the adjacent cores is not more than 1.6×10?5/m.

Abstract: A double clad fiber includes a core, a first cladding provided so as to cover the core, and a second cladding provided so as to cover the first cladding. The second cladding has a plurality of pores extending in a length direction and arranged so as to surround the first cladding. In at least one fiber end, the second cladding has been removed by mechanical processing so that the at least one fiber end is formed by the core and the first cladding.

Abstract: In an optical waveguide device of the present invention, optical element mount (17) includes first base block (19a) for supporting first optical element (18a) and second base block (19b) for supporting second optical element (18b) that has an active layer depth smaller than that of first optical element (18a). Second base block (19b) is formed from stacks of upper clad layers whose number of stacks is larger than that of first base block (19a). Difference (h1) in height between the first and second base blocks is equal to difference (d1?d2) in active layer depth between the first and second optical elements.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.

Abstract: An optical device includes an optical fiber having a core including multicomponent phosphate glasses, and a cladding surrounding the core, and a first fiber Bragg grating formed in a first portion of the core of the optical fiber and having an index modulation amplitude greater than 2×10?5.

Abstract: Since the magnitude of a nonlinear effect depends on the nonlinearity coefficient of the microstructured fiber and the intensity of pump light, either the nonlinearity coefficient or the intensity of pump light are adjusted. The nonlinearity coefficient is modified by introducing a nonlinear refractive index profile that has the inverse characteristic of the intensity distribution of either the pump or the signal light. The intensity of the pump light is adjusted by an optical amplifier, an optical attenuator, or a pre-emphasizing filter under the control of a control unit. The control unit controls the intensity of the pump light based on a look-up table which is prepared in advance by experiment or calculation, or based on a function of the pump and signal wavelength.

Abstract: Photonic band gap fibers are described having one or more defects suitable for the acceleration of electrons or other charged particles. Methods and devices are described for exciting special purpose modes in the defects including laser coupling schemes as well as various fiber designs and components for facilitating excitation of desired modes. Results are also presented showing effects on modes due to modes in other defects within the fiber and due to the proximity of defects to the fiber edge. Techniques and devices are described for controlling electrons within the defect(s). Various applications for electrons or other energetic charged particles produced by such photonic band gap fibers are also described.

Abstract: An arrangement comprising a fiber-optic waveguide (10) and a detection device (25), wherein the fiber-optic waveguide (10) comprises a core region (10E) and a cladding region (10C) surrounding the core region (10E), wherein the core region has a higher refractive index than the cladding region, and wherein the detection device (25) can detect damage to the fiber-optic waveguide (10).

Abstract: An optical sensor formed from an optical waveguide having at least one core surrounded by a cladding and a large diameter generally D-shaped portion is disclosed. Axial or compressive strain across the D-shaped cross section may be determined by measuring the change in polarization or birefringence of the light output from the sensor. A layer responsive to a parameter may be disposed on a flat portion of the D-shaped portion of the sensor. The refractive index of the layer changes and/or the layer applies a strain on the sensor in response to the parameter. Changes in the refractive index of the layer alters the light output from the sensor, which is measured over time and correlated to the parameter.

Abstract: A method for fabricating composite materials/devices comprising stacking together fibers or rods of at least two different materials and drawing the fibers or rods. Using this process, devices having nanoscale features can be readily fabricated.

Abstract: A gain medium operable to amplify light at a gain wavelength and having reduced transverse ASE includes an input surface and an output surface opposing the input surface. The gain medium also includes a central region including gain material and extending between the input surface and the output surface along a longitudinal optical axis of the gain medium. The gain medium further includes an edge cladding region surrounding the central region and extending between the input surface and the output surface along the longitudinal optical axis of the gain medium. The edge cladding region includes the gain material and a dopant operable to absorb light at the gain wavelength.

Abstract: The present invention relates to, for example, a method of easily manufacturing an optical fiber having any refractive index profile with fewer kinds of rods, and an optical fiber is manufactured by preparing a plurality of rods including at least two kinds of rods having different refractive indexes from each other, bundling rods selected from the plurality of rods to construct two or more rod units, producing a preform including a region in which the two or more rod units are combined so as to have a cross-sectional shape having rotational symmetry of order 2 or more, and manufacturing an optical fiber by drawing the preform.

Abstract: A resin composition is provided, which satisfies both an uncured layer flexibility requirement and a patterning resolution requirement for production of an optical waveguide by a roll-to-roll process. An optical waveguide produced by using the resin composition is also provided. The resin composition comprises: (A) an aromatic multifunctional epoxy polymer having a weight average molecular weight (Mw) of 500 to 5000; (B) an aromatic multifunctional epoxy polymer having a weight average molecular weight (Mw) of 10000 to 50000; (C) at least one of monofunctional, difunctional and trifunctional liquid aromatic epoxy monomers; and (D) a photoacid generator; wherein the components (A), (B) and (C) are present in proportions of 80 to 90 parts by weight, 5 to 15 parts by weight, and 1 to 10 parts by weight, respectively, based on a total of 100 parts by weight of the components (A), (B) and (C).

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: Certain embodiments of the invention may include systems and methods for providing tight-buffered optical fiber having improved fiber access. According to an example embodiment of the invention, a method for making a tight buffer upcoated optical fiber having a predetermined buffer stripping force is provided. The method includes controlling residual acrylate unsaturation (RAU) and oxygen in at least an outer surface of un-buffered optical fiber to achieve a predetermined buffer stripping characteristic, applying a tight buffer composition comprising acrylate to the un-buffered optical fiber, and curing the tight buffer composition.

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: A dispersion-shifted optical fiber (NZDSF) includes a central core (r1, Dn1), an inner cladding having at least three zones with a first intermediate cladding zone (r2, Dn2), a second ring zone (r3, Dn3) and a third buried trench zone (Wtr, Dnt). The buried trench zone has an index difference (Dnt) with the optical cladding between ?5·10?3 and ?15·10?3 and has a width (Wtr) between 2.5 ?m and 5.5 ?m. The present optical fiber, at a wavelength of 1550 nm, has reduced Rayleigh scattering losses of less than 0.164 dB/km, with limited bending losses.

Abstract: Microstructured optical fiber for single-moded transmission of optical signals, the optical fiber including a core region and a cladding region, the cladding region including an annular hole-containing region that contains non-periodically disposed holes. The annular hole containing region is doped with at least one dopant selected from fluorine and chlorine. The optical fiber provides low bend loss as well as low heat-induced splice loss.

Abstract: An optical device includes an electrooptic crystal substrate, a polarization-inverted region formed in a part of the electrooptic crystal substrate, an optical waveguide formed in the electrooptic crystal substrate, and a groove for relaxing stress disposed between a domain wall of the polarization-inverted region and the optical waveguide.

Abstract: Embodiments of the invention relate to a single-polarization fiber that may include a W-type refractive-index profile having a depressed region along an unguided principal axis of the fiber, and a quasi step-index profile along a guided principal axis of the fiber. The quasi step-index profile may have a depressed region with a radial extent at least twice that of the depressed region along the unguided axis.