Abstract: A multi-core optical fiber includes: a plurality of core portions; and a cladding portion positioned so as to surround each of the core portions, wherein each core portion includes a center core portion that has a refractive index greater than that of the cladding portion, a second core portion that is formed so as to surround the center core portion and that has a refractive index less than that of the center core portion, and a depressed portion that is formed so as to surround the second core portion and that has a refractive index less than those of the second core portion and the cladding portion, and an interval distance between the adjacent core portions is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than ?30 dB at a wavelength of 1.55 ?m.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

Abstract: Bend resistant multimode optical fibers are disclosed herein. Multimode optical fibers disclosed herein comprise a core region having a radius greater than 30 microns and a cladding region surrounding and directly adjacent to the core region, the cladding region comprising a depressed-index annular portion comprising a depressed relative refractive index. The fiber has a total outer diameter of less than 120 microns, and exhibits an overfilled bandwidth at 850 nm greater than 500 MHz-km.

Abstract: The present invention relates to an optical cable with a structure for improving a durability performance. The optical cable comprises, as a basic structure: a coated optical fiber, and a cable jacket covering an outer periphery of the coated optical fiber. The coated optical fiber is constituted by a glass fiber and a coating layer of an ultraviolet curing resin. To realize excellent impact resistance as durability performance, the coating layer of the coated optical fiber includes a first coating with a Young's modulus of 200 MPa or more. Meanwhile, the cable jacket is comprised of a thermoplastic resin that does not contain any halogens. The cable jacket has a thickness of 0.7 mm or more, a flame retardancy of V2 or more according to UL Standards, and a Young's modulus equal to or greater than that of the first coating.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

Abstract: Technologies are generally described for an optical waveguide, methods and systems effective to form an optical waveguide, and an optical system including an optical waveguide. In some examples, the optical waveguide may include a silicon oxynitride region in a wall of the silicon substrate. The silicon oxynitride region may define an inner region of the optical waveguide. The wall may define a via. The optical waveguide may include a silicon oxide region in the substrate. The silicon oxide region may define an outer region of the optical waveguide adjacent to the inner region.

Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

Abstract: A large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used.

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: 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: 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: 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: An optical fiber capable of suppressing an increase of a transmission loss after exposure of the optical fiber to hydrogen or deuterium is provided. The optical fiber has a core region, an inner cladding region surrounding the core region, a trench region surrounding the inner cladding region, an outer cladding region surrounding the trench region, and a refractive index varying region arranged between the inner cladding region and the trench region, the refractive index varying region having a refractive index gradually increasing from the trench region to the inner cladding region.

Abstract: The present invention embraces a single-mode optical fiber that, at a wavelength of 1550 nanometers, has bending losses of 0.15 dB/turn or less for a radius of curvature of 5 millimeters.

Abstract: Provided are a silica nanowire that includes silicon nanodots and a method of preparing the same. The silica nanowire has excellent capacitance characteristics and improved light absorption ability, and thus can be effectively used in a variety of fields, such as various semiconductor devices including CTF memory, image sensors, photodetectors, light emitting diodes, laser diodes, and the like.

Abstract: A rare-earth doped optical fiber that includes a core and one or more clad layers surrounding the core, in which the core has a rare earth dopant, and a relationship of Equation (1) is satisfied: 0 < ? r 0 r c ? D ? ( r ) · P p 2 ? ( r ) · P s 2 ? ( r ) ? r ? ? ? r ? r 0 r c ? D ? ( r ) · P p 2 ? ( r ) ? r ? ? ? r ? 0.35 ( 1 ) where Pp(r) represents an electric field distribution in an exciting wavelength, Ps(r) represents an electric field distribution in wavelengths of spontaneous emission and/or stimulated emission carried in the core, D(r) (mass %) represents a rare-earth dopant distribution, ro represents a core center, and rc represents a core radius.

Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

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 large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used.

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: 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: Disclosed is an optical transmission fiber having reduced bending and microbending losses that is commercially usable in FTTH or FTTC transmission systems.

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: 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: 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: Disclosed is a low bend loss optical fiber including: a core; an inner layer disposed at outside of the core, which has a refractive index lower than a refractive index of the core, the refractive index of the inner layer gradually decreasing as it becomes farther from the core; and a trench layer disposed at outside of the inner layer, which has a lowest refractive index.

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: 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: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

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: A light input/output terminal module 100 comprises a jacket tube 110 and a flange 120. A glass portion 20 of the optical fiber is inserted in the center portion thereof. To efficiently remove the leaked light in a cladding 22 to the jacket tube 110, the jacket tube 110 is made of silica glass or the same material as that of the cladding 22. The jacket tube 110 is fixed by fusion splicing or adhesion to the cladding so as to integrally unify the jacket tube 110 and the cladding 22. The beam diameter at the fiber end portion is enlarged by an optical component which fusion bonds the tip end of the optical fiber to the coreless fiber so that the optical power density at the light input/output terminal module is reduced.

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: A photonic bandgap optical fiber and a method of manufacturing said fiber is disclosed. The photonic bandgap fiber comprises a core region surrounded by cladding region. The cladding region includes a background optical material having a first refractive index, and elements of optical material having a second refractive index higher than said first refractive index. The elements are arranges periodically in the background optical material. At the drawing temperature of the fibered, the background optical material has a viscosity lower than the viscosity of the optical material of the elements.

Abstract: A photonic bandgap fiber includes a core and a cladding that surrounds the core. In this photonic bandgap fiber, high refractive index portions which have a refractive index higher than that of a medium of the cladding are provided in the cladding so as to form a triangular lattice structure with a lattice constant ?, and the refractive index of the core is higher than the refractive index of the medium of the cladding and lower than the refractive index of the high refractive index portion. The coupling length between the core and the high refractive index portion that is closest to the core is longer than the coupling length between adjacent high refractive index portions, or a periodic structure formed by the high refractive index portions is not provided around the entirely of the area along the circumference of the core.

Abstract: A photonic band-gap fiber comprises a first core having a refractive index that is not higher than a refractive index of a clad; a second core that is disposed so as to surround the first core and has a refractive index that is lower than the refractive index of the first core; a clad that surrounds the second core; and a periodic structure portion that is disposed in the clad in a vicinity of the second core and is constituted by high-refractive index portions that have a refractive index higher than that of clad and form the periodic structure, and the periodic-structure portion functions as a wave-length filter. By the function of the periodic structure portion as a wave-length filter, it is possible to reduce the propagation loss of the transmission wavelength and increase the propagation loss of the cutoff wavelength.

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: The present invention relates to a multi-core optical fiber having a structure for reducing transmission loss and nonlinearity. The multi-core optical fiber comprises plural cores extending along a center axis direction, and a cladding surrounding the peripheries of the plural cores. The cladding is comprised of silica glass doped with fluorine, and each of the plural cores is comprised of silica glass doped with chlorine or pure silica glass.

Abstract: A multimode optical fiber includes a central core, an inner cladding, a buried trench, and an outer cladding (e.g., an outer optical cladding). Typically, the optical fiber's central core is a glass-based central core having an alpha-index profile (i.e., a graded-index profile), an outer radius r1, and a maximum refractive index difference ?n1 with respect to the outer cladding. The central core's alpha-index profile has a minimum refractive index at the central core's outer radius r1 that corresponds to a refractive index difference ?nend with respect to the outer cladding. The inner cladding has an outer radius r2, a width w2, and a refractive index difference ?n2 with respect to the outer cladding. The buried trench has an outer radius rext, a width w3, and a refractive index difference ?n3 with respect to the outer cladding. The multimode optical fiber typically has reduced bending losses, a high bandwidth at wavelengths of both 850 nanometers and 1300 nanometers, and a reduced cladding effect.

Abstract: A 1.55 ?m band dispersion shifted optical fiber is provided which has a low loss and low dispersion slope. A core region “a” is heavily doped with GeO2 . A core region “b” is composed of pure SiO2 glass. A cladding section is arranged around the core region. The cladding section has a lot of holes extending in the longitudinal direction of the optical fiber. The holes of the cladding section are not located at random, but have a honeycomb structure composed of regular hexagons which have a side length of ?, and serve as a primitive lattice. The center of the core section has a region having a refractive index higher than that of the periphery of the core section. The core section has the refractive index distribution in which the group velocity dispersion at the operation wavelength of the region becomes the normal dispersion.

Abstract: An optical device includes an optical material comprising active dopant ions and absorber dopant ions spaced apart from the active dopant ions. The active dopant ions are provided to absorb a first radiation and convert a portion of the first radiation into sensible heat. A concentration profile of the absorber dopant ions is selected to absorb a second radiation different from the first radiation and optionally the first radiation in at least one direction of the optical material so as to control a refractive index profile in the at least one direction of the optical material.

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.

Abstract: A multimode optical fiber comprises a central core having an alpha profile, a depressed cladding having a portion in continuity with the alpha profile of the central core and a stepped portion, and an outer cladding. The alpha profile is obtained by co-doping at least two dopants. The variation in concentration of each dopant and its derivative in relation to the fiber radius are continuous. A multimode fiber for Ethernet optical system with an improved bandwidth is thus obtained.

Abstract: A multi-core optical fiber includes a plurality of core portions. The diameter of each of the core portions is 12 micrometers or smaller, the relative refractive-index difference of the core portions with respect to the cladding portion is 0.2% or larger, the cut-off wavelength is 1.53 micrometers or smaller, the bending loss at a 1.55-micrometer wavelength is 10 dB/m or smaller, the effective core area at a 1.55-micrometer wavelength is 30 ?m2 or larger, and the cross-talk of light between the core portions is ?35 decibels or smaller.

Abstract: An optical fiber that is relatively insensitive to 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 including (i) an outer cladding region having a refractive index less than that of the core region, (ii) an annular cladding pedestal region having a refractive index higher than that of the outer cladding region and comparable to that of the core region, and (iii) an annular cladding inner trench region disposed between the core region and the pedestal region, the inner trench region having a refractive index less than that of the outer cladding region. In one embodiment, the fiber also includes a (iv) an annular cladding outer trench region disposed between the pedestal region and the outer cladding region, the outer trench region having a refractive index less than that of the outer cladding region.

Abstract: An optical fiber that is relatively insensitive to 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 including (i) an outer cladding region having a refractive index less than that of the core region, (ii) an annular cladding pedestal region having a refractive index higher than that of the outer cladding region and comparable to that of the core region, and (iii) an annular cladding inner trench region disposed between the core region and the pedestal region, the inner trench region having a refractive index less than that of the outer cladding region. In one embodiment, the fiber also includes a(iv) an annular cladding outer trench region disposed between the pedestal region and the outer cladding region, the outer trench region having a refractive index less than that of the outer cladding region.

Abstract: An optical fiber is designed to transmit high-power laser radiation. The optical fiber includes a fiber core, and an inner fiber cladding surrounding the fiber core, where the inner fiber cladding is configured to carry the laser radiation in the fiber core. The optical fiber also includes a first outer fiber cladding surrounding the inner fiber cladding. The first outer fiber cladding has a capillary-free longitudinal section and has a smaller refractive index than the refractive index of the inner fiber cladding. The optical fiber includes an outermost fiber cladding surrounding the first outer fiber cladding. The outermost fiber cladding has scattering centers that surround the capillary-free longitudinal section, where the scattering centers scatter laser radiation emerging from the inner fiber cladding through the first outer fiber cladding along the capillary-free section.

Abstract: A fiber optic sensor apparatus includes an optical fiber, a fiber bend holder, and a sensing element. The optical fiber can be configured to form a transmit fiber path and a return fiber path by adhering the fiber bend holder to the center of the optical fiber in order to form a straight section between the transmit fiber path and the return fiber path. The optic fiber can be physically bent and adhered to tabs associated with the fiber bend holder. A cut can be precisely made in the center of the adhered straight section and the sensing element can be inserted into an optical path associated with the optical fiber.

Abstract: A non-zero dispersion shifted optical fiber (NZDSF) includes a central core, an inner cladding, and an outer cladding. The central core has an outer radius r1 and a maximum refractive index difference Dn1 with respect to the outer cladding. The inner cladding includes a first intermediate cladding and a buried trench. The first intermediate cladding has an outer radius r2 and a refractive index difference Dn2 with respect to the outer cladding. The buried trench has an outer radius r3, a width w3, and a negative refractive index difference Dn3 with respect to the outer cladding. In some embodiments, the inner cladding includes a second intermediate cladding having an outer radius r4 and a refractive index difference Dn4 with respect to the outer cladding. For a radius of curvature of 30 millimeters at a wavelength of 1625 nanometers, the optical fiber typically exhibits bending losses of about 0.5 dB/100 turns or less.

Abstract: The invention relates to a pump coupler (2) and a manufacturing method. The pump coupler (2) comprises a least one signal fiber (50) for outputting optical energy, multiple pump fibers (31) for inputting optical energy into the signal fiber (50), and a coupling structure (40) for coupling the optical energy of the pump fibers (31) into the signal fiber (50). A signal feed-through fiber (32) goes through the coupling structure (40). In accordance with the invention the coupling structure (40) is a tapering capillary tube (40) having a first wide end (65) and a second narrow end (70), the pump fibers (31) are connected to the wide end of the capillary tube (40), and at least the narrow end (70) of the capillary tube (70) is collapsed around the signal fiber (32).