Abstract: A method for manufacturing an optical fiber base material includes producing glass fine particles through a hydrolysis of a glass material gas in a flame created by an oxidizing gas and a combustible gas.

Abstract: An optical fiber manufacturing method, which recycles cooling gas with a simple system (less modification from a conventional device) is provided. The method comprises the steps of heating and melting an optical fiber preform, cooling the glass fiber obtained from the preform using a cooling device, and coating the cooled glass fiber with a coating material. During the cooling step, cooling gas is supplied from the bottom portion of the cooling device 4; a part of the cooling gas in the cooling device 4 is recovered from the top portion of the cooling device 4; and the recovered gas is re-supplied from the bottom portion of the cooling device 4.

Abstract: Provided is a ferrule holding member with a transparent body attached to an inner hole of a sleeve. The transparent body has a primary end face for bringing into contact with an end face of a plug ferrule at a halfway position in an axial direction of the sleeve. The primary end face of the transparent body has a convex curved surface obtained through heat treatment. The convex curved surface is preferably an unpolished surface, and a region with a radius of 75 ?m or more, centered around a shaft axis of the sleeve at the convex curved surface, has a convex spherical surface. Alternatively, the transparent body is directly fixed to an inner surface of the sleeve through heat treatment.

Abstract: A graded index multimode fiber and method of producing the graded index multimode fiber utilize a technique of reducing an index profile of the core of the multimode fiber below a standard parabolic index profile. This can be done by changing dopant concentrations in the fiber core over the radius of the fiber core. The result is a multimode fiber having differential mode delay characteristics that are intentionally not minimized. The index profile can be reduced below the standard parabolic index profile over the entire radius of the core, or only for radii above a specified radius.

Abstract: A device for coupling multimode pump light and a laser signal into or out of a cladding-pumped fibre laser is disclosed, comprising an output optical fibre, a substantially un-tapered feed-through optical fibre, an annular waveguide having a tapered section, and a plurality of multimode pump fibres such that: the signal feed-through fibre is located within the annular waveguide; the signal feed-through fibre is fused into the annular waveguide in the tapered section so that the annular waveguide becomes an additional cladding layer of the feed-through fibre; the end of the feed-through fibre that is fused into the annular waveguide is optically coupled to the output optical fibre; the multimode pump fibres are optically coupled to the annular waveguide in the un-tapered section. Methods of forming the device are also disclosed.

Abstract: The present invention discloses an improved optical device having at least a first and second optical components. The optical device further includes a first extending tube securely attached to the first and second optical components as a first building block wherein the first and second optical components are aligned and position adjusted in the position-holding-and-fixing means and securely attached thereto by a room-temperature UV curable epoxy UV cured at room temperature. The optical device then further assembled using a step-by-step building block assembling process with more building blocks assembled by optical components similar to the first building block described above. In other preferred embodiment, the first and second optical components held in the extending tube having a pre-aligned dihedral angle between the first and second optical components.

Abstract: Optical waveguide device has waveguide strip-shaped in the depth direction of the drawing and protruding from peripheral portion. A core (not illustrated) is disposed inside waveguide. Wall to be cut is integrated with waveguide to form one core layer. No unevenness occurs in a cutting line of wall indicated with broken line. Accordingly, high-precision cutting is enabled by cutting wall along the cutting line.

Abstract: The invention concerns a method for making an optical fiber (18) including the following steps: producing a preform (10) containing nanoparticles provided with an active element including at least one recess (14) proximate at least part of the nanoparticles; fiber drawing of the preform (10) by introducing a non-oxidizing gas in the recess (14), thereby limiting the risks of oxidizing the nanoparticles of the preform (10). The preform (10) designed to the manufacture of an optical fiber (18) by the inventive method comprises nanoparticles provided with an active element in a doped zone (12) and at least one recess (14) proximate the doped zone (12).

Abstract: Waveguide(s) (130) including at least partially buried channels) (120) within substrate(s) (100) having at least one substantially planar surface (110) are disclosed. According to some embodiments at least part of the channel (120) is located beneath at least a portion of the substrate (100). According to some embodiments the waveguide channel (120) includes a substantially transparent core (140) and optional cladding (160) extending through the channel (120). Alternately, an inner surface of the channel (120) is highly reflective. Furthermore, structures for use as waveguides (130) and/or as microchannels for fluid flow are disclosed herein. Also disclosed are production methods for such waveguides and said structures (130) and said structures, and methods of using such waveguides (130).

Abstract: Provided are a method and apparatus for manufacturing fiber gratings capable of removing or reducing birefringence and polarization-dependence caused by fiber gratings, and an optical fiber having the fiber gratings formed thereby. The method includes: selectively exposing an optical fiber to a light source, and generating first fiber gratings on the optical fiber; and selectively exposing the optical fiber to a light source on a region spaced apart from the first fiber gratings in a longitudinal direction at a different angle from the first fiber gratings about an axis of the optical fiber, and generating second fiber gratings that are the same as the first fiber gratings. Use of the method and apparatus for manufacturing fiber gratings may effectively remove or reduce birefringence or polarization effects.

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. In one case, the slot reaches the hollow core upon drawing, while in another case a second step is used to extend the slot to connect to the hollow core. The fiber is used to form an environmental sensor for sensing the presence of a target substance in an environment. The slot formed in the PBG region of the fiber forms a ridge waveguide wherein a portion of the light that otherwise is confined to the hollow core as a bound mode travels in the slot.

Abstract: The present invention relates to an optical interconnection structure and a method for manufacturing the same. The optical interconnection structure includes a silicon substrate on which at least one groove formed with a lens is formed to have a curvature radius on the upper surface thereof; and a silica layer that is formed on the silicon substrate including the groove formed with the lens to retain a shape of the groove formed with the lens. As a result, there are effects that the optical interconnection structure can be manufactured in great quantities by performing most of the processes using a semiconductor processing equipment and have better thermal characteristics than that of the existing PCB substrate.

Abstract: A CMOS processing compatible germanium on silicon integrated waveguide photodiode. Positioning contacts in predicted low optical field regions, establishing side trenches in the silicon layer along the length of the photodiode reduces optical losses. Novel taper dimensions are selected based on the desirability of expected operational modes, reducing optical losses when light is injected from the silicon layer to the germanium layer. Reduced vertical mismatch systems have improved coupling between waveguide and photodiode. Light is coupled into and/or out of a novel silicon ring resonator and integrated waveguide photodiode system with reduced optical losses by careful design of the geometry of the optical path. An integrated waveguide photodiode with a reflector enables transmitted light to reflect back through the integrated waveguide photodiode, improving sensitivity. Careful selection of the dimensions of a novel integrated waveguide microdisk photodiode system results in reduced scattering.

Abstract: A method for manufacturing an optical fiber includes the steps of covering an outer periphery of a first glass (11) having a first softening temperature and a non-axisymmetric structure by a second glass (12, 13) having a second softening temperature which is lower than the first softening temperature, heating the first and second glasses (11, 12, 13) for fusion together to thereby obtain an optical fiber preform; and drawing the preform to the optical fiber.

Abstract: The present invention is a method of fabricating a waveguide using a sacrificial spacer layer. The first step in this process is to fabricate the underlying optical semiconductor structure. A trench is then etched in this structure and a sacrificial spacer layer is deposited in the trench. The waveguide is then created in the trench on the sacrificial spacer layer. User-defined portions of the sacrificial spacer layer are subsequently removed to create air gaps between the waveguide and the sidewalls of the trench in the optical semiconductor.

Abstract: A cable assembly comprising a fiber optic cable and one or more attachment points to allow one or more tethers to optically connect to optical fibers within the cable. The cable assembly may be used as a drop cable for extending optical connections to a plurality of points. An attachment structure is provided for maintaining the tether to the cable to prevent damage to the tether. The attachment structure provides a loose attachment to allow the tether to move relative to the distribution cable, so the tether can move in a generally translational movement, is able to slightly twist, and to have limited lateral movement during coiling, installation, and removal of the cable assembly. This loose attachment structure may prevent damage to the tether due to forces being placed on the cable, such as during coiling or uncoiling of the cable. In one exemplary embodiment, the attachment structure is attached to the cable and receives the tether.

Abstract: A method of fabrication of a thermally stabilized Type I fiber Bragg grating-based temperature sensing device includes doping a fiber core material with germanium or germanium oxide for enhancing photosensitivity, co-doping the fiber core material with fluorine or chorine or for increasing a mean coordination number; and ultraviolet laser inscribing a periodic or quasiperiodic modulated refractive index structure in the fiber core using a laser energy operating at less than 1000 milliJoules per square centimeter per pulse. The resulting sensor is operable for more than 1000 hours at temperatures up to at least 550 degrees Celsius.

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

Abstract: A method of manufacturing a microlens substrate having a plurality of microlenses includes the steps of: preparing a substrate having two major surfaces and a plurality of concave portions formed in one of the two major surfaces, each of the concave portions having a shape corresponding to that of each of the microlenses being formed in the one of the two major surfaces of the substrate; preparing a base material substrate formed of glass having a transformation point lower than that of a constituent material constituting the substrate; and pressure-joining the substrate to the base material substrate in a heating state. In the pressure-joining step, the substrate is joined to the base material substrate and the concave portions fill with the glass material of the base material substrate which is melted by the heat.

Abstract: A method of forming a longitudinal solid body within at least one longitudinal hole formed in an optical fiber, comprising the steps of placing a first end and a portion of the optical fiber in a heating chamber; keeping a second end of said optical fiber outside of the heating chamber; forcing a molten material into the longitudinal hole of the fiber from the first end; and thereupon longitudinally extracting the optical fiber from the heating chamber at a controlled rate. Preferably, the fiber is extracted while molten material is being urged into the fiber.

Abstract: An optical fiber made of silica-based material includes a core and a cladding formed around the core. The core is doped with germanium dioxide, which increases refractive index and decreases acoustic-wave velocity, and aluminum oxide, which increases both refractive index and acoustic-wave velocity, satisfying—2.814+0.594×W1?W2?54.100+0.218×W1, W1+W2?60, and W2?56.63?2.04×W1, where W1 is doping amount of germanium dioxide in weight percentage, which is larger than 4.74, and W2 is doping amount of aluminum oxide in weight percentage. A nonlinear coefficient of the optical fiber is equal to or larger than 2.6×10?9W?1.

Abstract: A fiber-optic component comprises a hollow casing defining an enclosed cavity therewithin, a fiber-optic unit disposed within the cavity, and a potting compound filling the cavity in the casing and encapsulating the fiber-optic unit of the fiber-optic component. The potting material has a compressive strength allowing the fiber-optic component to withstand pressure of up to 14,000 psi. A method for manufacturing the fiber-optic component comprises the steps of: providing the casing with the enclosed cavity therewithin, inserting the fiber-optic unit into the cavity, providing the potting material, and introducing the potting material into the cavity so that a space around the fiber-optic unit is filled with the potting material to encapsulate the fiber-optic unit.

Abstract: A method for manufacturing a single mode optical fiber with a reduced PMD (Polarization Mode Dispersion), by drawing an optical fiber preform composed of a core and a clad surrounding the core, includes (a) heating the optical fiber preform to a high temperature using a furnace, and drawing an optical fiber from an outlet of the furnace at a linear velocity (Vf) of 500 mpm or above by means of neck-down drawing; and (b) impressing a spin on the optical fiber by means of a spin impressing device provided on a drawing path of the optical fiber, wherein a maximum spatial frequency of spin (y) impressed on the optical fiber satisfies the following equations Exp ? ( 24 ? t - 12 ) ? y ? - 20 × log ( V f 500 ) + 25 and t=(0.21×CladOval)+(0.04×CoreOval)+(0.17×ECC), where y is a maximum spatial frequency of spin [turns/m], Vf is a drawing velocity [mpm], CladOval is a clad ovality [%], CoreOval is a core ovality [%], and ECC is an eccentricity [?m].

Abstract: The glass fiber for an optical amplifier has a matrix glass core, a first glass cladding, and a second glass cladding. The matrix glass core has a composition, in mol %, of Bi2O3, 30-60; SiO2, 0.5-40; B2O3, 0.5-40; Al2O3, 0-30; Ga2O3, 0-20; Ge2O3, 0-25 ; La2O3, 0-15; Nb2O5, 0-10; SnO2, 0-30; alkali metal oxides, 0-40; and Er2O3, 0.05-8. The glass claddings have the same composition as the core, except that a transition metal compound is included as an absorbent. The refraction index of the matrix glass is > about 1.85, the refraction index of the first glass cladding is less than that of the core, and the refraction index of the second glass cladding is higher than that of the first.

Abstract: A light guide includes a transparent sheet exhibiting total internal reflection in at least one direction and phosphor printed on the transparent sheet. The phosphor extracts light from the transparent sheet when the sheet is edge-lit and converts the light from one wavelength to another wavelength. The phosphor is pressed into the surface of the sheet after heating the surface to its softening temperature.

Abstract: A method of fiber core material band gap engineering for artificially modifying fiber material properties is provided. The method includes doping the fiber core material with one or more atoms for enhancing photosensitivity to the fiber material. The method also includes co-doping the fiber core material with one or more ions for enhancing an amorphous network crosslink mean coordination number. The method further includes thermally annealing the fiber core material for widening the band gap of the fiber core material.

Abstract: The present invention concerns an optical fiber 10 comprising a substantially pure silica glass core 12, a concentric tin-doped core/cladding interface region 14, and a concentric fluorine-doped depressed cladding layer 16. The tin-doped core/cladding interface region 14 comprises a low concentration gradient of tin dioxide, which advantageously results in a de minimis refractive index change, resistance to hydrogen incursion, and thermal stability of any fiber Bragg gratings written into the interface region 14.

Abstract: A single-mode optical fiber segment incorporating liquid-filled holes parallel to the core that are sealed at each end. Heating the liquid produces stress in the fiber and thereby increases the birefringence level. Alternatively the holes may be filled and sealed at a temperature lower than the temperature at which the fiber will be operated, the temperature difference determining the stress level for given hole characteristics.

Abstract: Disclosed is an optical fiber having a silica-based core and a silica-based cladding, the core comprising germania, and oxides of an alkali metal and phosphorous. By appropriately selecting the concentration of alkali metal and phosphorous oxides, fibers exhibiting low attenuation and low hydrogen aged attenuation may be obtained. In a preferred embodiment, the alkali metal oxide is potassium oxide (K2O).

Abstract: A core rod is inserted into a cladding pipe, moisture in a space between the core rod and the cladding pipe is removed, and an optical fiber is drawn while the space is connected to a dry-gas atmosphere and/or being decompressed and while the core rod and the cladding pipe are being unified with each other. Alternatively, the core rod is inserted into the cladding pipe, and an optical fiber is drawn from one end while moisture on the surface of the core rod and the internal surface of the cladding pipe is being removed. Accordingly, a high quality optical fiber is manufactured with good productivity.

Abstract: Optical waveguide device has waveguide strip-shaped in the depth direction of the drawing and protruding from peripheral portion. A core (not illustrated) is disposed inside waveguide. Wall to be cut is integrated with waveguide to form one core layer. No unevenness occurs in a cutting line of wall indicated with broken line. Accordingly, high-precision cutting is enabled by cutting wall along the cutting line.

Abstract: A Bragg grating that has an average index of refraction that changes with temperature to compensate for variations in grating spacing caused by temperature changes.

Abstract: A preform (15) having a clad part of PVDF and a core part of PMMA is manufactured. The preform (15) is partially heated in a heating furnace (74) of 240° C. The preform (15) is subject to the melt-drawing process to form a plastic optical fiber (17). The drawing tension to the preform (15) is measured by use of a drawing tension measure device (76). Based on the measured value, a drawing roller pair (78) adjusts the drawing tension to be 3.8 MPa. The plastic optical fiber (17) is fed via a dancer roller (82) and rollers (84, 86) toward a bobbin (87) to wind the plastic optical fiber (17). A winding tension measure device (85) measures the winding tension to the POF (17). Based on the measured value, the dancer roller (82) changes its position to adjust the winding tension to be 2.5 MPa.

Abstract: A method provided for manufacturing a lensed tip optical fiber. The method includes providing an optically transparent cylindrical fiber; and etching a first end of the optically transparent cylindrical fiber to form a tip. The tip is heated which forms a lens surface at the heated tip.

Abstract: The present invention provides a method of manufacture that minimizes the lateral offset of a plurality of optical fiber holes associated with a multi-fiber ferrule, including: determining an initial offset distance of each of the plurality of optical fiber holes from each of a plurality of corresponding target locations on an initial endface; removing a predetermined amount of material from the multi-fiber ferrule to form a subsequent endface; determining a subsequent offset distance of each of the plurality of optical fiber holes from each of the plurality of corresponding target locations on the subsequent endface; and, using the initial offset distance and the subsequent offset distance, determining an angle of each of the plurality of optical fiber holes relative to the initial endface.

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

Abstract: An optical fiber which, at an optical fiber connecting end having a plurality of voids around the periphery of a core, has a light-permeable substance, such as a resin or glass whose refractive index is lower than that of quartz type substances, filled in the voids adjacent to the connecting end. An optical fiber connecting section where an optical fiber having a plurality of voids in a clad around the periphery of a core is connected to another optical fiber, wherein the optical fiber is connected end-to-end to aforesaid another optical fiber through a refractive index matching agent whose refractive index at the minimum temperature in actual use is lower than that of the core.

Abstract: Briefly, in accordance with one or more embodiments, a thermally controlled optical filter comprises a frame coupled to an etalon where the frame includes a resistive thermal device disposed on the frame to obtain thermal measurements of the etalon during operation. The frame may be generally L-shaped or generally square-shaped. The frame may include a fillet that is generally planar, generally beveled or trapezoidal, or generally circular in shape. A heater may be additionally disposed on the frame. The etalon and frame subassembly may be bonded to a micro hot plate that is capable of heating the etalon to an operational temperature.

Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: Provided is an optical transmission substrate including: a first substrate; an optical waveguide which has clad covering a core and a periphery of the core and extends on an upper surface of the first substrate; a second substrate provided parallel to the first substrate so that a lower surface thereof contacts an upper surface of the optical waveguide; a reflection surface which is provided on a cross section of the core at an end of the optical waveguide and reflects light, which travels through the core of the optical waveguide, toward the second substrate; and a light guide which is provided in the second substrate and guides the light, which is reflected toward the second substrate, toward an upper surface of the second substrate from a position closer to the core than an upper surface of the clad.

Abstract: Included among the many structures described herein are photonic bandgap fibers designed to provide a desired dispersion spectrum. Additionally, designs for achieving wide transmission bands and lower transmission loss are also discussed. For example, in some fiber designs, smaller dimensions of high index material in the cladding and large core size provide small flat dispersion over a wide spectral range. In other examples, the thickness of the high index ring-shaped region closest to the core has sufficiently large dimensions to provide negative dispersion or zero dispersion at a desired wavelength. Additionally, low index cladding features distributed along concentric rings or circles may be used for achieving wide bandgaps.

Abstract: A method is provided for producing an optical acoustic sensor. In one embodiment, a method comprises winding a single-mode optical sensor fiber around at least one mandrel. The optical acoustic sensor fiber can comprise a core region having a diameter of about 2 ?m to about 8 ?m and a cladding region having an outer diameter of about 8 ?m to about 20 ?m. The method can also comprise interconnecting the at least one mandrel into an optical acoustic sensor.

Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: Disclosed is an optical fiber cable that includes a main tube. A guide tube, which includes at least one optical element, is positioned within the main tube's central space. A compressible element is also positioned within the main tube's central space. To reduce the adverse effects of ice formation within the optical fiber cable, the compressible element more readily deforms than do the guide tube and main tube. Also disclosed is a method for modifying a conventional optical fiber cable with a compressible element according to the present invention.

Abstract: A microstructured optical fiber exhibiting enhanced circularity of the guided light mode is provided. The microstructured optical fiber includes a light-guiding core and a primary cladding surrounding the core wherein the primary cladding has a plurality of holes arranged in hexagonal unit cells defining an Archimedean-like lattice. Preferably, the core is defined by a break in a center of the Archimedean-like lattice, the break being characterised by an absence of at least one of the unit cells. Also preferably, each of the unit cells has seven holes arranged in a centred hexagon. A method of making the microstructured optical fiber is also provided. The method includes fabricating a fiber preform by stacking a plurality of canes around a rod, each cane having a number of holes arranged in a unit cell defining an Archimedean-like lattice, and drawing said fiber preform into the microstructured optical fiber.

Abstract: A CMOS processing compatible germanium on silicon integrated waveguide photodiode. Positioning contacts in predicted low optical field regions, establishing side trenches in the silicon layer along the length of the photodiode reduces optical losses. Novel taper dimensions are selected based on the desirability of expected operational modes, reducing optical losses when light is injected from the silicon layer to the germanium layer. Reduced vertical mismatch systems have improved coupling between waveguide and photodiode. Light is coupled into and/or out of a novel silicon ring resonator and integrated waveguide photodiode system with reduced optical losses by careful design of the geometry of the optical path. An integrated waveguide photodiode with a reflector enables transmitted light to reflect back through the integrated waveguide photodiode, improving sensitivity. Careful selection of the dimensions of a novel integrated waveguide microdisk photodiode system results in reduced scattering.

Abstract: An optical fiber array substrate 11 has, in one surface thereof, eight V-grooves 12 for securing eight optical fibers 14 aligned in parallel to each other, and V-shaped side grooves 13 formed outside of the respective outermost V-grooves 12 located at the opposite sides of the substrate 11. The apexes of the outside ridges 12c and 12d defining the outermost V-grooves 12 are at the same height as the apexes of the inside ridges 12a and, the height of the bottom 13a of the side groove 13 is lower than that of a contact point 12e between the ridge line of the V-groove 12 and optical fiber 14.

Abstract: There is provided a method for manufacturing an optical fiber base material. The method includes: connecting a dummy rod 3 to an end of a target formed of a quartz glass rod to form a rod with dummy, the target becoming the optical fiber base material by depositing thereon glass particles; forming a taper portion 10 of which a diameter of the dummy rod side is narrower than a diameter of the target side in a connecting portion between the dummy road being chucked and the target 5 when processing the rod with dummy to transparently vitrify it; and depositing glass particles on an outer circumference of the glass rod with dummy after the processing the dummy rod so as to cover the outer circumference of a large diameter side of the taper portion 10 and forming soot.

Abstract: The present invention intends to provide a two-dimensional photonic crystal having a high level of mechanical strength and functioning as a high-efficiency resonator. The two-dimensional photonic crystal according to the present invention includes a slab layer 31 under which a clad layer 32 is located. In the slab layer 31, areas 35 having a refractive index different from that of the slab layer 31 are cyclically arranged to create a two-dimensional photonic crystal. A portion of the cyclic arrangement of the areas 35 are omitted to form a point-like defect 36. This defect 36 functions as a resonator at which a specific wavelength of light resonates. An air-bridge cavity 37 facing the point-like defect 36 is formed over a predetermined range of the clad layer 32. In this construction, the clad layer 32 supports the slab layer 31 except for the range over which the air-bridge space 37 is formed. Therefore, the two-dimensional photonic crystal has a high level of mechanical strength.

Abstract: The lead-free optical glass can be used in the fields of imaging, sensor technology, microscopy, medical technology, digital projection, photolithography, laser technology, wafer/chip technology, as well as of telecommunications, optical communication engineering and optics/lighting in the automotive sector. It has a refractive index nd of 1.82?nd?2.00 and/or an Abbe number vd of 18?vd?28 with good chemical stability, excellent crystallization stability and the following composition, in wt. based on oxide content, of: P2O5 12-35 Nb2O5 30-50 Bi2O3 ?2-13 GeO2 0.1-7?? Li2O ?6 Na2O ?6 K2O ?6 Cs2O ?6 MgO ?6 CaO ?6 SrO ?6 BaO ???7-<17 ZnO ?6 TiO2 ?7 ZrO2 ?7 WO3 ?2-14 F ??6.