Abstract: The invention relates to fused silica having low compaction under high energy irradiation, particularly adaptable for use in photolithography applications.

Abstract: A laser beam is used to ablate the outer cladding of an extended portion of an optical fiber. The laser beam is focused at a tangential point on the outer cladding. The laser can be rotated around the optical fiber while the optical fiber is held stationary. Alternatively the optical fiber can be rotated while the focal point of the laser beam is kept at a constant position.

Abstract: A method of making an optical waveguide preform includes forming a preform including a first portion and a second radial portion, wherein the second portion includes a dopant, and wherein the first portion exhibits a density greater than the second portion. The method further includes stripping at least a portion of the dopant from the second portion. In a preferred embodiment, the stripped dopant has migrated in a previous processing step.

Abstract: A tube-encased fiber grating includes an optical fiber 10 having at least one Bragg grating 12 impressed therein which is embedded within a glass capillary tube 20. Light 14 is incident on the grating 12 and light 16 is reflected at a reflection wavelength &lgr;1. The shape of the tube 20 may be other geometries (e.g., a “dogbone” shape) and/or more than one concentric tube may be used or more than one grating or pair of gratings may be used. The fiber 10 may be doped at least between a pair of gratings 150,152, encased in the tube 20 to form a tube-encased compression-tuned fiber laser or the grating 12 or gratings 150,152 may be constructed as a tunable DFB fiber laser encased in the tube 20. Also, the tube 20 may have an inner region 22 which is tapered away from the fiber 10 to provide strain relief for the fiber 10, or the tube 20 may have tapered (or fluted) sections 27 which have an outer geometry that decreases down to the fiber 10 and provides added fiber pull strength.

Abstract: An optical conductor includes a transparent fiber of synthetic material, a reflective layer and a sheathing of synthetic material. The optical conductor is rotationally symmetrical relative to a fiber axis. The property and the position of the end race of the fiber are of decisive significance for the optical quality of a plug connection of two optical conductors. The ends of the optical conductors must be arranged at a minimum spacing one from the other and the fiber axes must be oriented exactly one onto the other. Usually, the end of the optical conductor is mounted in a ferrule, in which case it is important that, in a plug connection, the one end face is positioned exactly relative to the other end face. The projecting fiber end is severed by a laser beam, wherein an end face arises, which displays the required mechanical and optical qualities.

Abstract: A method for manufacturing an optical grating on a length of optical fiber having input and output ends. Guided light is conducted into the input end of the fiber and light reflected back from the output end is measured with an optical sensor. An optical grating is formed in the fiber between the input and output ends and guided light is conducted into the input end of the fiber and light reflected back from the grating is measured with an optical sensor. Measured light is compared to determine a percentage of guided light reflected back from the grating.

Abstract: A method for manufacturing a discharge tube, including heating a quartz tube by irradiation and closing it shut, is presented, in which variation of the heating temperature of the quartz tube can be reduced. Laser light is irradiated on a portion of the quartz tube, and in the step of sealing the portion of the quartz tube onto which laser light has been irradiated, the laser light is scanned while oscillating back and forth. The intensity of the laser light is controlled such that the intensity of the laser light when the size of a displacement of the laser light is maximal is smaller than the intensity of the laser light when the size of the displacement of the laser light is minimal.

Abstract: Thermal 3-D microstructuring of photonic structures is provided by depositing laser energy by non-linear absorption into a focal volume about each point of a substrate to be micromachined at a rate greater than the rate that it diffuses thereout to produce a point source of heat in a region of the bulk larger than the focal volume about each point that structurally alters the region of the bulk larger than the focal volume about each point, and by dragging the point source of heat thereby provided point-to-point along any linear and non-linear path to fabricate photonic structures in the bulk of the substrate. Exemplary optical waveguides and optical beamsplitters are thermally micromachined in 3-D in the bulk of a glass substrate. The total number of pulses incident to each point is controlled, either by varying the rate that the point source of heat is scanned point-to-point and/or by varying the repetition rate of the laser, to select the mode supported by the waveguide or beamsplitter to be micromachined.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: A system and a method for curing a coating applied to an optical fiber or optical fiber ribbon using a laser curing device which emits a plurality of laser beams, having a predetermined wavelength or wavelength range, that impinge on the fiber or ribbon at differing angles to provide a uniform cure. The system includes at least one laser for outputting a laser beam; a splitter for splitting the laser beam into a plurality of output beams; and reflector arrangement for reflecting the output beams such that the output beams are irradiated on the coating of the optical fiber from different angles. The reflector comprises a plurality of mirrors or, alternatively, a housing, which substantially surrounds the optical fiber where at least a portion of an inner surface of the housing is reflective. Alternatively, the reflector may be replaced with a bundle of UV-waveguides directing portions of the beam to the substrate at different angles and/or directions.

Abstract: A method of attaching a component onto a microbench includes laying the component in a groove in the substrate, and locally deforming a portion of the groove, to thereby hold the component in the groove. Preferably, the microbench is a silicon substrate used for MEMs-type structures in the fiber optics industry. In particular, the method is used for securing an optical fiber in a groove, DRI etched from a silicon substrate, before or after the fiber is aligned with other optical components, i.e. lenses, lasers etc. The local deformation is done using a laser welding device selected to be effective in locally melting the substrate while leaving the component relatively undamaged.

Abstract: A laser gain medium and a method of manufacturing a laser medium, such as a laser rod, or slab for use in high-powered laser peening systems. A laser medium and method reduces stress risers along the surface of the amplifier medium by grit blasting, polishing, etching, annealing, and by eliminating platinum inclusions within the laser glass.

Abstract: An apparatus and method for manufacturing chiral fibers having chiral fiber Bragg gratings properties from UV sensitive optical fibers by using a UV laser beam to impose a chiral modulation of the refractive index at the core of the fiber.

Abstract: Optical fiber diffusers for emitting light cylindrically along a length of the fiber diffuser with preselected light intensity distributions along the length of the diffuser. The diffuser portion is defined by forming a Bragg grating in a section of the optical fiber core having a modulated index of refraction which acts to couple light radially out of the fiber along the diffuser section. The intensity distribution of light coupled out of the diffuser section of the fiber is controlled by controlling the profile of the modulated index of refraction, namely the coupling coefficient, along the length of the grating. For photodynamic therapy type II strong Bragg gratings are preferred which give higher intensity output over short distances. Multiple Bragg gratings can be written into a multimode fiber for emission of light at several positions along the fiber.

Abstract: Methods, systems, and apparatus consistent with the present invention use a beam of laser energy to concentrically form an optical preform from two or more concentric glass objects, such as two glass tubes or a hollow glass tube and a solid glass rod. The glass objects are placed in a concentric configuration where the outer object has an inner surface that is placed proximate to an outer surface of the inner object. Once these are assembled, a beam of laser energy is generated, positioned, and applied to a starting point in the gap defined by the inner surface and the outer surface. Once the laser beam is applied and is reflecting down into the gap, the beam of laser energy is moved relative to the starting point as the beam is concurrently applied. This heats the inner surface and outer surface so that the two objects can be joined to form the optical preform. In another aspect of the invention, a coating layer is disposed within the gap and can be heated by the laser as it is applied within the gap.

Abstract: There is provided a device and method for forming optical fiber anti-symmetric long period gratings by microbending. In the optical fiber grating forming device, a laser system emits a CO2 laser beam, a lens focuses the CO2 laser beam on an optical fiber in a predetermined width, an optical fiber support fixes both ends of the optical fiber and imparts tensile strain to the optical fiber, and a controller controls the intensity of the CO2 laser beam, the focusing distance of the lens, and the tensile force applied by the optical fiber support.

Abstract: The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: A silica glass is provided for use in an optical system processing an excimer laser beam. The silica glass has a molecular hydrogen concentration of about 5×1018 molecules/cm3 or less and is substantially free from defects which become precursors susceptible to an one-photon absorption process and a two-photon absorption process upon irradiation of the excimer laser beam to the silica glass.

Abstract: Devices are made comprising a tin-phosphorous oxyfluoride glass, which has been exposed to light, preferably shorter in wavelength than the absorption edge of the glass, to change the refractive index change of the glass. The glasses can be used to form planar and fiber devices, including core/clad structures for guiding light.

Abstract: The present invention is a process for manufacturing an optical fiber Bragg grating, which in a preferred embodiment includes the steps of: (a) removing at least a portion of a removable coating on an optical fiber element in at least one predetermined section to sufficiently expose the optical fiber in the section for a subsequent treatment by a source of optical radiation; (b) fixing the at least one section with respect to the source of optical radiation; (c) directing optical radiation from the source into the optical fiber to produce at least one Bragg grating in the at least one section; and (d) covering the at least one section. The present invention also extends to an apparatus for carrying out the process steps described above, which includes means for coating removal, means for fiber immobilization, means for writing a Bragg grating, and means for packaging.

Abstract: A tunable chirped grating device for an optical fiber, wherein the grating has equal spacings between index perturbations. A piezoelectric element is bonded to the optical fiber for changing the perturbation spacings according to an applied voltage, and a voltage source applys the voltage to the piezoelectric element. Since a predetermined piezoelectric element is bonded to an optical fiber provided with a grating having regular spacings and the perturbation spacings can be differently deformed by applying different electric field to respective perturbation positions by the piezoelectric element, then the resulting in a chirped grating device, whose manufacturing procedure is simple and which has flexibility, can provide adjustable chirping rates of the reflected wavelengths waves.

Abstract: A process for cutting or splitting at least one optical fiber at a predetermined angle, wherein the fiber is introduced into a holding and positioning device and is cut by a pulsed laser beam.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: To manufacture polarization-maintaining optical fibers, a fiber is directly and continuously irradiated with at least one beam of UV radiation during drawing and before application of external coatings.

Abstract: A method for fabricating an optical waveguide, comprising the following steps. That is, forming an optical waveguide on surface of a substrate via an atmospheric pressure chemical vapor deposition (AP-CVD) method using a silica raw material containing an organic material, and irradiating ultraviolet light on at least a portion of that optical waveguide. The refractive index of the portion of the optical waveguide irradiated with ultraviolet light increases. Since changing the refractive index in this way enables the formation of a diffraction grating, it is possible to manufacture optical filters and wavelength dispersion devices.

Abstract: A glass 1 is irradiated with a focused pulsed laser beam 2 having a peak power density of 10.sup.5 W/cm.sup.2 or more and a repetition rate of 10 KHz or more. The glass 1 irradiated with the laser beam 2 changes its refractive index at the focal point 4. During the laser beam irradiation, the glass 1 is continuously moved with respect to the focal point of the pulsed laser beam 2 or continuously scanned with the focused laser beam 2, so as to form the refractive index changed region (i.e. an optical waveguide 5) with a predetermined pattern. The glass 1 in which the optical waveguide 5 will be formed may be any kind of glass having high transparency.

Abstract: A method for controlling a bore diameter of an optical fiber ferrule is disclosed. The diameter of the bore is controlled by collapsing the ferrule around a rod inserted in an over-sized bore formed therein. The diameter of the rod is selected to match the diameter of the optical fiber to be supported by the ferrule. Thus, after the rod is subsequently immersed in liquid nitrogen removed from the ferrule, the ferrule has a bore diameter which is defined by the diameter of the rod. Suitable materials for the ferrule and the rod include glass and metal, respectively.

Abstract: In the method of drawing fiber continuously from preforms for manufacturing an optical fiber, a first preform is displaced along a fiber-drawing axis and is drawn into an optical fiber through a fiber-drawing furnace disposed on the fiber-drawing axis, and a second preform is displaced along the fiber-drawing axis, which second preform is butt welded to the first preform so as to be drawn into an optical fiber following on from the first fiber. The two preforms are butt welded, i.e. they are welded together end-to-end, by displacing at least one power laser along the fiber-drawing axis, and by servo-controlling the displacement of said laser to the displacement of the two preforms so as to maintain a laser beam emitted by the power laser at the same height as the two ends to be welded together, thereby making it possible to reduce considerably the size of the zone affected by the welding, and to avoid polluting the side surfaces of the two preforms upstream and downstream from the weld.

Abstract: An excellent quartz glass optical member having stable laser beam resistance, can be obtained by preparing quartz glass in a process having:a first step of subjecting a starting material obtained from silicon halide, alkoxysilane, alkylalkoxysilane, etc. to an oxidizing heat treatment in a temperature range between 600 and 1,500.degree. C., to decrease the hydrogen concentration to 5.times.10.sup.16 molecules/cm.sup.3 or less and at the same time eliminate reducing defects;a second step of subsequently holding the quartz in a hydrogen-containing atmosphere in a temperature range between 200 and 600.degree. C., to establish a hydrogen concentration in the glass of 1.times.10.sup.17 molecules/cm.sup.3 ; anda third step of carrying out a treatment of making the hydrogen concentration of the resultant quartz glass uniform in an atmosphere of air, inert gas, hydrogen, a mixture of hydrogen and inert gas, or a mixture of air and inert gas in a temperature range between 300 and 800.degree. C.

Abstract: A laser surface method involves applying a laser beam treatment in one or several steps to a series of generally similar surfaces of given depth. Properties of the laser treatment are selected so as to change the physical state of each surface. Ellipsometry measurements are made in a region of the first surface before application of the laser beam treatment to the second surface, so as to obtain a physico-chemical characterization of the first surface. Both the laser beam application and the ellipsometry measurement are conducted under generally similar working conditions, so that the change of the physical state of each surface produced by the laser treatment can be controlled in a real time, in-situ, rapidly and nondestructively.

Abstract: The present invention provides a process for substantially extending the useful life of fused silica elements used in high energy ultraviolet optical systems. The fused silica bulk material is pre-compacted by illuminating it with radiation prior to final mechanical fabrication and polishing to the required final surface figure. When the optical element is subsequently used in a high energy ultraviolet environment, it will continue to be compacted but at a lower effective rate. As a result, the useful life of fused silica optical elements can be increased substantially.In preferred embodiments the fused silica material is precompacted with multiple passes of short-pulse ultraviolet radiation. Multiple passes can reduce precompaction time. In one example useful life of the fused silica is increased from about 150 days to 3.8 years by about 5 days of precompaction.

Abstract: An apparatus for producing an optical fiber porous glass preform using the VAD method which can stably produce a high quality optical fiber porous glass preform, wherein a target bar is only rotatably supported by a chuck and is not pulled upward, a lower tip of a soot body is detected by a laser and a photodetector, and a core burner and a cladding burner is lowered in response to the result detected. A tip position detecting drive and burners are synchronizingly lowered while the deposit of porous glass grows at the lower portion of the target bar.

Abstract: An optical fiber (7) exhibits varying transmission characteristics in different strain states and can have an S-shaped microbend. For producing such a fiber it is heated locally in a small region, as viewed in the longitudinal direction of the fiber, and then the portions of the fiber (1) located at the two sides of the heated region are displaced in relation to each other in a transverse direction in relation to the longitudinal direction of the fiber. It can be performed in a conventional fusion-splicing apparatus for optical fibers. Alternatively, a laser can be used as a heating source, what is particularly suitable for processing optical fibers having longitudinal cavities in order to infer to it similar transmission characteristics. The optical fibers produced by this method are suited for use as sensors, e.g. strain gauges.

Abstract: A method of producing an optical waveguide grating by exposure to light. An optical waveguide having a core composed of a material wherein the refractive index changes due to exposure to UV light is formed into an optical waveguide grating by applying a grating portion formation step wherein a grating portion is formed by irradiation with UV light at a predetermined spacing, and an overall exposure step after formation of the grating portion wherein the entire grating portion is irradiated with UV light. As a result, the effective refractive index of the grating portion is changed so as to allow the central wavelength to be adjusted without changing the rejection. Consequently, the grating properties can be precisely and easily controlled.

Abstract: A method of manufacturing an optical fiber having a core portion doped with a dopant and a surrounding optical cladding portion is disclosed. The method comprises the steps of drawing a fiber from a molten extremity of a silica preform and moving the fiber along towards a device for coating it with a protective sheath. Prior to the coating step, the moving fiber is irradiated with irregularly modulated actinic radiation, thereby causing corresponding irregular variations in the refractive index of its core portion as a function of longitudinal position. The resulting fiber demonstrates a significantly reduced polarisation mode dispersion.

Abstract: A glass is irradiated with a focused pulsed laser beam having a peak power density of 10.sup.5 W/cm.sup.2 or more and a repetition rate of 10 KHz or more. The glass irradiated with the laser beam changes its refractive index at the focal point. During the laser beam irradiation, the glass is continuously moved with respect to the focal point of the pulsed laser beam or continuously scanned with the focused laser beam, so as to form the refractive index changed region (i.e. an optical waveguide) with a predetermined pattern. The glass in which the optical waveguide is formed may be any kind of glass having high transparency.

Abstract: For forming bores for insertion of optical fibers, etc., on one side surface of a micro lens with high accuracy and easy work, a laser processing method that includes the steps of: irradiating a laser beam onto the one side surface of the micro lens; then focusing the laser beam in a layer having superiority in absorbency with respect to the laser beam; and forming the bores because the laser beam exceeds the threshold value of causing fusion, evaporation or ablation in the superior laser beam absorption layer.

Abstract: A furnace body for a glass preform elongating apparatus which makes an elongated body by passing the glass preform through the furnace body and elongating the glass preform while heating the glass preform, the furnace body comprising a furnace core tube shaped like a cylinder through which the glass preform passes and having so adequate length in an axial direction that the elongated body may not bend or distort its form, a heating member disposed at an outer peripheral portion of the furnace core tube, a thermal insulator enveloping the furnace core tube and the heating member from outside in circumferential and axial directions thereof, and a furnace body outer shell holding the thermal insulator therein, wherein a through hole is disposed near the heating member downstream thereof in an advancing direction of the glass preform so as to penetrate through the furnace core tube, thermal insulator, and furnace body outer shell in the direction orthogonal to the furnace core tube.

Abstract: The present invention relates to a method for changing the refractive index in an element comprising germanium silicate glass by irradiating the germanium silicate glass with laser radiation having an associated wavelength in the range of 270 nm to 390 nm for exciting an absorption band in the glass centered at 330 nm. The element may be polymer coated in which instance the glass is irradiated through the polymer coating. In addition, the glass may have been exposed to a hydrogen atmosphere before being irradiated. In either instance, the laser radiation is directed at an angle to the surface of the element or along an optical axis of the element or both. The element may comprise a portion of an optical light guide, such as an optical fiber, or such as an integrated optical waveguide.

Abstract: A cladding-pumped fiber structure, suitable for use as a laser, provides for efficient clad-to-core energy transfer. The outside interface of the pump-clad is constructed from a rod-shaped preform by local melt-displacement using an open flame.

Abstract: The end face (32) of the optical fiber (24) of a fiber optical terminal (10) is finished by installing the fiber in a terminal ferrule (18), cleaving an end of the fiber close to the end face (54) of the ferrule, and heating the cleaved fiber end face so as to soften its end face and cause it to assume a smooth, rounded configuration. The heating is accomplished, for a glass fiber, by application of the beam of a carbon dioxide laser (60) to the optical fiber end face. The heat softened end face assumes a smooth, rounded configuration that minimizes back reflection. A system including a laser (105), shutter (102), beam expander (108) and parabolic mirror (110) heats the fiber end face that is positioned at the parabola faces by a three axis manipulator (156,158) and holder (152). Orthogonal viewing systems (126, 142) enable visual monitoring of the process.

Abstract: A method for producing a SiO.sub.2 glass material having regions changed in light refractive index is provided which comprises implanting at least 5.times.10.sup.19 Ge ions/cm.sup.3 into a SiO.sub.2 glass substrate, heat-treating the substrate at a temperature exceeding 300.degree. C., and exposing the substrate to an ultraviolet light. Also provided is a SiO.sub.2 glass material produced by the method.

Abstract: Optical waveguides are produced in laser densified Type VI porous gel-silica. A CO.sub.2 laser directly scans the substrate having a pore size of about 30 angstroms. Tracks having a width of about 50 microns are produced.

Abstract: Recognizing the rate-determining nature of the coating removal and recoating steps, applicants have demonstrated that with proper combination of low absorbing polymer, glass and low intensity radiation, UV-induced gratings can be side-written into polymer coated fibers without removing the polymer, thus permitting up the possibility of high speed fabrication of fiber gratings.

Abstract: Low attenuation, low dispersion of optical waveguides are provided by a process initiating with axial deposition of a high velocity core soot stream impinging on, a target at a high angle of incidence relative to the axis of rotation of the target. A core cylinder is built up axially by relative movement between the soot stream and target during deposition, the movement being non-constant in order to maintain a substantially constant diameter with a constant deposition rate. A cladding layer is then built up by deposition of soot radially on the core. Subsequent drying and sintering provides a vitreous preform which may be drawn directly into optical waveguides. Alternatively, the sintered product may be drawn down to smaller rods, which then are covered with further deposited soot cladding to a desired final thickness, and after further drying and sintering may be drawn to optical waveguides.

Abstract: In accordance with the invention, the index of refraction of a glassy material is increased by treating the material with hydrogen and applying heat. Specifically, the glass is exposed to hydrogen or deuterium at pressure in the range 14-11,000 p.s.i. and a temperature in the range 21.degree.-150.degree. C. for a time sufficient for the hydrogen to diffuse into the glass. The glass is then subjected to heat in excess of about 500.degree. C., as by application of a flame or infrared radiation. The duration of heating can be less than a second. The result is a substantial and long-lived increase in the normalized refractive index. For example, flame heating of H.sub.2 loaded commercial GeO.sub.2 doped optical fibers (AT&T Accutether single mode fiber) has produced normalized index changes .increment.n/n of 4.times.10.sup.-3. This process can be used to make and adjust a variety of optical waveguide devices.

Abstract: In order to fabricate strip monomode active optical waveguides for optical elecommunications, a layer of vitreous soot is deposited on a substrate and is impregnated with a solution of a precursor of a rare-earth dopant, and a radiation with a wavelength comprised in an absorption band of the dopant is moved along the soot, along a trajectory corresponding to the geometrical shape desired for the guide, thereby forming a vitrified strip.

Abstract: A method of making a preform for an optical fiber, in which method a plurality of layers of fluoride glass are deposited inside a support tube (10); said layers (14) are deposited by laser ablation in a controlled atmosphere using a target (12) having the composition of said glass, which target is moved back-and-forth parallel to the axis of said tube, the temperature of the enclosure (1) in which said ablation is performed being not greater than the vitreous transition temperature Tg of said glass.