EP1427677A2 - Glass fibre with at least two glass layers - Google Patents
Glass fibre with at least two glass layersInfo
- Publication number
- EP1427677A2 EP1427677A2 EP02779323A EP02779323A EP1427677A2 EP 1427677 A2 EP1427677 A2 EP 1427677A2 EP 02779323 A EP02779323 A EP 02779323A EP 02779323 A EP02779323 A EP 02779323A EP 1427677 A2 EP1427677 A2 EP 1427677A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- glass
- core
- cladding
- glass fiber
- fiber according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01265—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt
- C03B37/01274—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt by extrusion or drawing
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
- C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
- C03B37/022—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from molten glass in which the resultant product consists of different sorts of glass or is characterised by shape, e.g. hollow fibres, undulated fibres, fibres presenting a rough surface
- C03B37/023—Fibres composed of different sorts of glass, e.g. glass optical fibres, made by the double crucible technique
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C13/00—Fibre or filament compositions
- C03C13/04—Fibre optics, e.g. core and clad fibre compositions
- C03C13/045—Silica-containing oxide glass compositions
- C03C13/046—Multicomponent glass compositions
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/062—Glass compositions containing silica with less than 40% silica by weight
- C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
- C03C3/068—Glass compositions containing silica with less than 40% silica by weight containing boron containing rare earths
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/12—Silica-free oxide glass compositions
- C03C3/253—Silica-free oxide glass compositions containing germanium
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/08—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
- C03B2201/10—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with boron
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/32—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with aluminium
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/34—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers
- C03B2201/36—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers doped with rare earth metals and aluminium, e.g. Er-Al co-doped
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/10—Internal structure or shape details
- C03B2203/22—Radial profile of refractive index, composition or softening point
- C03B2203/23—Double or multiple optical cladding profiles
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
- G02B6/03616—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference
- G02B6/03622—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 2 layers only
- G02B6/03627—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 2 layers only arranged - +
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
- G02B6/03616—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference
- G02B6/03638—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 3 layers only
- G02B6/0365—Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference having 3 layers only arranged - - +
Definitions
- the present invention relates to a glass fiber which comprises a core, the matrix glass of which contains at least one heavy metal oxide and at least one rare earth compound, the core being surrounded by at least two glass jackets. Furthermore, the present invention relates to a method for producing a glass fiber according to the invention, an optical amplifier which comprises at least one glass fiber according to the invention, and the use of the glass fiber according to the invention.
- Optical amplifiers are one of the most important key components in optical communications technology.
- a purely optical telecommunications signal is transmitted in an optical fiber, intrinsic signal attenuation inevitably occurs.
- highly efficient optical amplifiers are required which can amplify a signal without the optical signal having to be converted into an electronic signal and back again into an optical signal.
- the speed of the amplification can also be increased by optical amplifiers, and the deterioration of the signal-to-noise ratio is considerably less due to the elimination of the conversion into electronic signals and back.
- Stray light can arise in optical amplifier fibers by various mechanisms, which can lead to a deterioration in the signal-to-noise ratio and should therefore be avoided or removed as completely as possible.
- Previously available polymer coatings always have a lower refractive index than heavy metal oxide glasses. Coating with such polymers to absorb scattered light is therefore problematic, since only a polymer jacket with a lower refractive index can be provided.
- Each coating with a cladding made of a material with a lower refractive index then leads to a strong and undesirable reflection at the interface of this material with the core regions or an inner cladding.
- EP 1 127 858 describes a light-intensifying glass whose matrix glass is doped with 0.01 to 10 mol% Er, the matrix glass necessarily 20 to 80 mol% Bi 2 O 3 , 0.01 to 10 mol% CeO 2 , and contains at least one of B 2 0 3 or SiO 2.
- the glass fibers described in the publication are only provided with conventional polymer coatings. The same applies to the glasses containing high antimony oxide described in WO 99/51537.
- JP 11274613 A describes a glass fiber comprising glasses with a high refractive index, which has two glass jackets. According to this scripture
- the object of the present invention was therefore to provide a glass fiber, comprising a matrix glass with at least one heavy metal oxide, for an optical amplifier, with which the problems of the prior art described above can be avoided.
- this glass fiber should make it possible to minimize the noise caused by stray light and thus to increase the signal power of the amplifier.
- the present invention relates to a glass fiber comprising a core, the matrix glass of which contains at least one heavy metal oxide and at least one rare earth compound, the core being surrounded by at least two glass jackets and the refractive index jump ⁇ n from the core to the first jacket in the range from 0.001 to 0.08 and the first cladding has a lower refractive index than the core.
- Figure 1 shows a schematic cross section through a particularly preferred embodiment of the glass fiber according to the invention.
- FIGS 2, 5 and 7 show photographic images of the cross section through glass fibers according to the invention with two glass jackets.
- FIG. 3 and 4 show schematically preferred fiber design of the double sheath fibers according to the invention with two and three sheaths, respectively.
- FIG. 6 shows the comparison of the absorbing action of iron oxide and cobalt oxide as the absorbing agent in a bismuth oxide-containing glass melted under strongly oxidizing conditions.
- FIGS. 8a and 8b show the maximum gain calculated from Giles parameters for a fixed number of channels as a function of the wavelength, and the change in noise as a function of the wavelength.
- FIGS. 9a and 9b show the energy transmitted in the core area, in the area of the first cladding and in the area of the second cladding for different fiber lengths depending on the doping of the outer cladding.
- the core of the glass fiber according to the invention preferably contains at least one heavy metal oxide which is selected from oxides of Bi, Te, Se, Sb, Pb, Cd, Ga, As and / or mixed oxides and / or mixtures thereof.
- the matrix glass of the core particularly preferably contains heavy metal oxides which are selected from oxides of Bi, Te, Sb and / or mixtures thereof.
- the matrix glass of the core further comprises at least one dopant that can be excited by light.
- the matrix glass of the core contains rare earth ions as dopants.
- a dopant is understood to mean a component which is only added to the glass in a small amount and which therefore does not substantially influence most of the physical properties of the glass, such as Tg, the refractive index or the softening temperature. However, such a dopant can have a significant influence on certain, in particular optical properties, such as the ability to optically stimulate.
- the matrix glass of the core preferably comprises at least one rare earth compound which consists of compounds of Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb,
- Dy Ho, Er, Tm, Yb and / or Lu is selected.
- Oxides are particularly preferred of the elements Er, Pr, Tm, Nd and / or Dy, with oxides of Er being most preferred.
- Sc and / or Y compounds can also be contained in the glass according to the invention.
- the rare earth compounds used as dopants are preferably so-called “optically active compounds”, “optically active compounds” being understood in particular to mean those which lead to the glass according to the invention being capable of stimulated emission when the glass is excited by a suitable pump source.
- At least two rare earth compounds in a total amount of 0.01 to 15 mol% can also be used.
- Glasses with optically active rare earth ions can be codoped with optically inactive rare earth elements, for example to increase the emission lifetimes.
- it can be coded with La and / or Y.
- it can, for example, also be codoped with other optically active rare earth compounds, such as Yb.
- Gd can be codoped to stabilize the crystallization.
- sensitizers such as Yb, Ho and Nd can be added in an appropriate amount, for example 0.005 to 8 mol%.
- each individual rare earth compound is, for example, from 0.005 to 8 mol%, preferably 0.05 to 5 mol%, on an oxide basis.
- the matrix glass comprises both Ce and Er.
- the matrix glass of the core is cerium-free.
- the glass fiber according to the invention contains at least one Bi 2 O 3 glass in the core and / or in one or more sheaths.
- the following compositions are particularly preferred:
- M 1 is at least one of Li, Na, K, Rb and Cs and M 11 is at least one of Be, Mg, Ca, Sr, Ba and / or Zn. It is particularly preferred that Li and / or Na is M 1 to be used.
- FIGS. 8a and 8b show the gain and the noise of a doped HMO double cladding fiber according to the invention compared to SiO 2 reinforcing fibers as a function of the wavelength and the number of channels.
- Giles parameters are determined using methods known from the prior art for the amplifier fibers, from which the maximum gain and the noise at a specific wavelength are then determined when the number of channels is specified.
- FIG. 8a shows on the one hand that with a set number of 120 channels [ch], a maximum gain of approximately 25 dB is achieved with an amplifier fiber according to the invention, while only one for a silicatic amplifier fiber with the same number of channels maximum gain of just under 20 dD is achieved.
- the number of channels must be reduced from 120 to 80 channels for a silicate amplifier fiber.
- the noise of the glass fiber according to the invention is significantly lower than that of a silicate fiber.
- the fiber according to the invention has a higher maximum gain with less noise.
- the glass fiber according to the invention comprises at least two glass jackets which surround the core.
- the cladding glasses are not subject to any particular restriction. They preferably have similar physical properties to the matrix glass of the core and / or the glass of the other cladding, in particular a similar refractive index, a similar Tg and a similar softening temperature.
- the jackets comprise essentially the same composition like the core, but the compositions are modified in such a way that the necessary refractive index strokes from the core to the first jacket and, if appropriate, from one jacket to another jacket are fulfilled.
- core and cladding glasses preferably differ in their optical properties.
- the cladding glasses among one another preferably have different optical properties.
- the “first sheath” is understood to mean the sheath surrounding the core.
- the shells are numbered from the first sheath outwards to higher numbers.
- the mentioned refractive indices are the refractive indices or refractive indices of the glasses for electromagnetic radiation in the near IR range, in particular at about 1300 nm.
- the refractive index jump ⁇ n from the core to the first cladding is from 0.001 to 0.08, particularly preferably from 0.003 to 0.04, more preferably from 0.005 to 0.05, the first of which the cladding has a lower refractive index than the core.
- the refractive index ratio of the cladding to one another can be adjusted as required by methods known in the art. To set a slightly higher refractive index than in the comparison glass, for example, a proportion of at least one component with a lower refractive index is switched to at least one component with a higher refractive index.
- the refractive index n m2 of the second cladding is substantially the same or preferably higher than the refractive index n m ⁇ of the first cladding. According to other embodiments, however, the refractive index of the second cladding can also be smaller than that of the first cladding and a third cladding is added, which has a higher refractive index than the second cladding. Particularly preferred embodiments are discussed further below.
- the glass of the cladding furthermore contains no rare earth doping, in particular no doping with optically active rare earth compounds. According to this embodiment, the amplification and guidance of the light mode (s) preferably takes place in the core.
- the glass of the first cladding contains small amounts of the rare earth compound (s) used as doping in the core.
- Doping of the first cladding with up to half the proportion, particularly preferably up to one third of the proportion, of the proportion used in the core is preferred.
- the signal / noise ratio of an amplifier fiber can be improved by this measure and that the coupling of the amplifier fiber to SiO 2 fibers is also improved. It is assumed that, with large core radii, the signal mode and the pump mode overlap more effectively with the rare earth ions also in the shell.
- the glass contains at least one cladding, in particular the outermost cladding, at least one absorbent component or an absorbent.
- absorbent components transition metal compounds, for example compounds of iron (in particular Fe 2+ and Fe 3+ ), nickel (in particular Ni 2+ ), cobalt (in particular Co 2+ ), manganese (in particular Mn 2+ ), copper (in particular Cu + and Cu 2+ ), vanadium (in particular V 3+ and V 4+ ), titanium (in particular Ti 3+ ) and / or chromium (in particular Cr 3+ ), and / or rare earth compounds.
- the doping with Fe 2+ can be several 100 ppm (based on the weight ratio).
- the composition of the second jacket can otherwise correspond to that of the core glass.
- the amount of absorbent to be added depends on the absorbent power of the absorbent. Fractions of 5 ppm, preferably 10 ppm, may already suffice for example with Co 2+ . The arrival is preferably some at most 5000 ppm, more preferably 2000 ppm, most preferably at most 1000 ppm are added. If higher proportions of absorbent are added to the glass composition, the properties of the glass, such as the crystallization properties, can be adversely affected. Therefore, this is not preferred.
- iron oxides are not suitable as an absorbent. It was found that, in particular, bismuth oxide in the molten state can be reduced to elemental bismuth, which leads to the precipitation of black metallic Bi and thus to a deterioration in the optical properties of the glass. Glasses which contain polyvalent heavy metal oxides such as bismuth oxide are therefore preferably melted under strongly oxidizing conditions.
- the glass fiber according to the invention is used as an optical amplifier for the 1.5 ⁇ m band, the so-called C band, due to its absorption band in the near infrared range, Fe 2+ ions could serve as a suitable absorber.
- Co 2+ ions which also have a suitable absorption in the near infrared range, are not converted into a higher oxidation state even by strongly oxidizing conditions in the melt and therefore as an absorbent in such a glass are particularly suitable.
- the outermost jacket therefore preferably contains at least one preferably oxidic, divalent cobalt compound as the absorbent.
- FIGS. 9a and 9b show the energy transmitted in the core 40 and the sheaths 42 and 44 of two types of glass fibers according to the invention.
- FIG. 9a shows the transmitted energy of a fiber according to the invention, the outer jacket 44 of which is doped with iron as an oxidizing agent.
- the different curves 30 to 36 correspond to different fiber lengths.
- FIG. 9a shows that with longer fiber lengths, the energy transmitted in the second jacket 44 becomes smaller in relation to the energy transmitted in the core 40 and the first jacket 42.
- FIG. 9b shows the corresponding energy transfer as a function of the radius of a glass fiber whose outer jacket 44 is doped with cobalt.
- the absorption effect of the second jacket is much more effective in this case. Hardly any energy is transferred in the outer jacket.
- the absorption effect is independent of the fiber length.
- FIG. 3 and 4 schematically show two particularly preferred designs of a glass fiber according to the invention.
- the refractive index as a function of the radius of the glass fiber is shown schematically.
- the core of the glass fiber according to the invention is surrounded by exactly two glass jackets.
- FIG. 1 shows a preferred embodiment of the glass fiber 1 according to the invention in section.
- the core 2 is surrounded by an inner jacket 3, which in turn is surrounded by an outer jacket 4.
- the outer jacket further contains an absorbent as described above.
- FIG. 3 shows a particularly preferred design of the refractive indices of a double cladding fiber.
- the region 11 is the core of the fiber which is generally approximately in the middle of the fiber and is doped with at least one rare earth compound
- the region 12 is the inner cladding and has a lower refractive index than the core region 11, which means that guidance of the light propagating in the area of the core is guaranteed.
- Region 13 is the " second, and here outer, cladding, which is primarily intended to absorb stray light.
- the refractive index of the second cladding can be higher than the refractive index of the core as shown here, but can also have the same or a lower refractive index than the core. As a rule, such an outermost cladding has a higher refractive index than the inner cladding adjoining it.
- the core of the glass fiber according to the invention is surrounded by exactly three glass jackets.
- FIG. 4 shows a particularly preferred design of a glass fiber according to the invention with three glass jackets.
- the region 21 represents the core of the fiber which is generally in the center of the glass fiber and which is doped with Er 3+, for example, and which carries the signal mode.
- the inner cladding 22 can contain a doping of Yb 3+ .
- Such doping of the first cladding with, for example, Yb 3+ can be used for a so-called multimode pumping. While in single or single-mode pumps, light is only radiated into the core area of the amplifier fiber and only very small and therefore very expensive lasers can be used, in multimode pumps, the broader cross-sectional area of the core and additionally the first cladding is irradiated.
- This irradiation excites Yb 3+ at approx. 975 nm ( 2 F 72 - » 2 F 52 ). Since Yb 3+ shows fluorescence on a similar wavelength, this fluorescence pumps the level ln / 2 of the Er 3+ ion at approx. 980 nm.
- the for Light sources that can be used with multimode pumps are considerably less expensive.
- the area of the second jacket 23 adjoining the first jacket 22 with a lower refractive index than the first jacket ensures that the light propagating in the area of the first jacket 22 is guided and the area of the third jacket 24 in turn serves as an outer absorbent jacket.
- the glass fiber according to the invention preferably has an essentially circular cross section.
- glass fibers are also encompassed by the present invention, which have a cross section deviating from a circular cross section.
- the core of the glass fiber according to the invention is generally in the middle of the glass fiber according to the invention, the sheaths preferably being arranged coaxially around the core.
- the present invention also includes embodiments in which the core is not in the middle of the glass fiber.
- the glass fiber according to the invention preferably comprises exactly one core. According to other embodiments, however, several core fibers can also be contained in the glass fiber according to the invention.
- the glass fiber according to the invention preferably has a total thickness of 100 to 400 ⁇ m, more preferably 100 to 200 ⁇ m. A total thickness of approximately 125 ⁇ m is particularly preferred.
- the core of the glass fiber according to the invention preferably has a diameter of 1 to 15 ⁇ m for use as an optical amplifier fiber.
- the first jacket preferably has a thickness d m1 in the range from 5 to 100 ⁇ m.
- the second and further sheaths preferably have a thickness d m 2 in the range from 10 to 150 ⁇ m.
- the core and / or shells can also have any other thickness.
- the term “core of a glass fiber” is to be understood as the area which was produced by the glass-technological manufacturing process and which differs from the sheath.
- a “core region” or “core area”, on the other hand, comprises the area in which the intensity of the optical signal has dropped to the e-th part of the input intensity.
- the glass fiber according to the invention comprises at least one coating on the outermost glass jacket, which comprises at least one plastic or one polymer.
- This outer plastic coating is used in particular for mechanical protection of the glass fiber.
- the thickness of this plastic coating is preferably from 2 to 400 ⁇ m. A value below 2 ⁇ m can usually not guarantee adequate protection of the glass fiber.
- the thickness is particularly preferably at least 3 ⁇ m, more preferably at least 8 ⁇ m. With thicknesses above 400 ⁇ m, it becomes difficult to provide a uniform coating.
- the thickness is particularly preferably at most 70 ⁇ m.
- plastics Any type of polymer can be used for such a plastic coating, as long as it adheres well to the cladding glass.
- plastics are thermosetting silicone resins, UV-curable silicone resins, acrylic resins, epoxy resins, polyurethane resins and polyimide resins, and also mixtures and / or blends thereof.
- the present invention further relates to a method for producing the glass fiber according to the invention, wherein at least two cladding glasses are formed around a core glass.
- This can be produced by production processes such as a “rod-in-tube” process, multiple crucible process and extrusion process, and combinations of these processes.
- a “preform” is first produced consisting of a core and one or more sheaths, which already has the layer structure of the later glass fiber and is made into a glass fiber. can be pulled.
- a preform has, for example, a thickness of 4 to 30 mm and a length of 5 to 40 cm. This preform is drawn into a fiber at a suitable temperature.
- a hole is drilled in a strand-shaped or rod-shaped cladding glass, so that a tubular cladding glass is obtained.
- a suitable rod of the core glass is inserted into this.
- the cladding glass can also be formed by suitable shaping processes For example, a rod of core glass with a diameter of 1.0 to 1.4 mm is inserted into a tubular first jacket with a diameter of the inner hole of 1.5 mm and an outer diameter of 7 mm To obtain the core surrounded by more than one jacket, this method can be repeated several times, ie for a second jacket a hole is drilled in a second rod-shaped jacket glass and the preform of the core and the first jacket is inserted into the tubular second jacket and jackets are heated to preferably join above the transformation temperature to get a "preform".
- a preform made of core and at least one first jacket can be pulled out to a certain extent after such heating and inserted in this pulled-out form as a rod into a second or further jacket.
- a hot-formed, drawn-out rod can also be inserted into a hot-formed, drawn-out tube.
- such a preform can also be produced by a so-called extrusion process.
- a block of the core glass is placed on a block of a cladding glass and then heated in a linear manner from the underside.
- the core glass slowly sags into the cladding glass along the heated line until it is completely enclosed by it.
- a “preform” consisting of a core or one or more shells is generated directly from the melt by crucibles that lie one inside the other.
- a glass fiber with a diameter of, for example, 125 ⁇ m can be produced.
- triple or multiple crucible processes are used for direct fiber production.
- a double crucible process for producing a “preform” from the core and the first jacket and the preform obtained in this way consisting of the core and a jacket by a “rod-in-tube” process as a rod to be inserted into a tubular second jacket. It has been found that this combination on the one hand provides a particularly good interface between the core and the first cladding, and on the other hand a second and / or additional cladding can be added economically.
- the present invention further relates to an optical amplifier which comprises at least one glass fiber according to the invention.
- the optical amplifier has the following structure.
- the incoming light signal is connected to a coupler via an optical isolator to suppress light reflections.
- the signal and pump light are combined in the coupler and coupled together into the optically active fiber.
- the other end of the amplifier fiber is connected to the outgoing fiber.
- a filter can also be arranged with another optical isolator if necessary his. It is also possible to pump the amplifier fiber in both directions, in which case a second coupler is required.
- the signal light source is connected to the wave-mixing optical coupler through the optical isolator.
- the optical coupler is also connected to the excitation light source. Then the optical coupler is connected to one end of the optical fiber. The other end of the optical fiber is connected to the optical isolator through the optical coupler for wave splitting. Each part is connected to the optical fiber.
- the present invention comprises the use of the glass fiber according to the invention as optically active glass in a laser arrangement.
- Table 1 shows the compositions of the glasses in mol%.
- the core glass drawn out into a strand was coated with the first jacket (outer diameter 7 mm; diameter inner hole: 1.5 mm) using the rod-in-tube method.
- the preform consisting of the core and the first jacket was then pulled out to a diameter of 1 mm and encased in a further rod-in-tube step with the outer jacket (outer diameter 7 mm; inner hole diameter 1.5 mm).
- the preform obtained was drawn out to a glass fiber with a thickness of 125 ⁇ m.
- FIG. 2 shows a photographic illustration of a cross section through a glass fiber according to the invention.
- Core 2 is surrounded by first jacket 3, which in turn is surrounded by outer jacket 4.
- a double cladding fiber was made using the same compositions as in Example 1, in which case the core was sheathed to the first cladding by a double crucible process.
- the core diameter and the dimensions of the first jacket corresponded to those of Example 1.
- the preform obtained in this way comprising the core and the first jacket, was then pulled out to a thickness of 1.5 mm.
- the second jacket was then formed by the rod-in-tube process around the extended preform from the core and the first jacket.
- the preform obtained was drawn out to a glass fiber with a thickness of 125 ⁇ m.
- FIG. 7 shows a photograph of the cross section through a fiber obtained according to Example 2.
- a double cladding fiber with tellurium oxide-based core and cladding glasses was produced by the process described in Example 1.
- the preform obtained was drawn out to a glass fiber with a thickness 4 of 325 ⁇ m and a core diameter of 4.5 ⁇ m.
- Figure 5 shows a cross section through the Te double-cladding fiber produced.
- the cross-section was etched so that the transitions from the core to the first cladding or the second cladding are more pronounced.
- a double cladding fiber was produced using the glass compositions shown in Table 2.
- a preform was made from the core and the first jacket using a double crucible. This preform was then provided with the second jacket using the rod-in-tube process. The preform obtained was then drawn out to a glass fiber with a diameter of 125 ⁇ m.
- Table 2
- a double cladding fiber was produced using the glass compositions shown in Table 3. First, a preform was made from the core and the first jacket using a double crucible. This preform was then provided with the second jacket using the rod-in-tube process. The preform obtained was then drawn out to a glass fiber with a diameter of 125 ⁇ m.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Glass Compositions (AREA)
- Lasers (AREA)
- Laminated Bodies (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
Claims
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10144475 | 2001-09-10 | ||
DE2001144475 DE10144475B4 (en) | 2001-09-10 | 2001-09-10 | Glass fiber with at least two glass jackets, process for their production and their use |
DE10211247 | 2002-03-13 | ||
DE2002111247 DE10211247A1 (en) | 2002-03-13 | 2002-03-13 | Glass fiber used in an optical amplifier in telecommunications and as a laser component comprises a core having matrix glass containing a heavy metal oxide and a rare earth compound |
PCT/EP2002/010058 WO2003022768A2 (en) | 2001-09-10 | 2002-09-07 | Glass fibre with at least two glass layers |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1427677A2 true EP1427677A2 (en) | 2004-06-16 |
Family
ID=26010103
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP02779323A Withdrawn EP1427677A2 (en) | 2001-09-10 | 2002-09-07 | Glass fibre with at least two glass layers |
Country Status (6)
Country | Link |
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US (2) | US7515802B2 (en) |
EP (1) | EP1427677A2 (en) |
JP (2) | JP2005503008A (en) |
CN (1) | CN1275891C (en) |
AU (1) | AU2002342664A1 (en) |
WO (1) | WO2003022768A2 (en) |
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- 2002-09-07 EP EP02779323A patent/EP1427677A2/en not_active Withdrawn
- 2002-09-07 WO PCT/EP2002/010058 patent/WO2003022768A2/en active Application Filing
- 2002-09-07 AU AU2002342664A patent/AU2002342664A1/en not_active Abandoned
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Also Published As
Publication number | Publication date |
---|---|
WO2003022768A3 (en) | 2003-11-27 |
CN1553883A (en) | 2004-12-08 |
AU2002342664A1 (en) | 2003-03-24 |
JP2007129243A (en) | 2007-05-24 |
US7515802B2 (en) | 2009-04-07 |
CN1275891C (en) | 2006-09-20 |
WO2003022768A2 (en) | 2003-03-20 |
US20040252961A1 (en) | 2004-12-16 |
JP2005503008A (en) | 2005-01-27 |
US20090158778A1 (en) | 2009-06-25 |
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