DE102011110247A1 - Method for fabricating preform for manufacturing bend-optimized optical fiber, involves changing outer diameter of rotationally symmetric rod and/or tube and/or individual module by compression or stretching operation - Google Patents

Abstract

The method involves applying protective, intermediate and/or barrier layer (3) on an inner and/or external surface (2,4) of casing tube. The outer and/or inner deposition of light-conducting layers (6) is performed on inner and/or outer surface of jacket pipe. An outer diameter of rotationally symmetric rod and/or tube and/or individual module is changed by a compression or stretching operation, so that heating and/or annealing and/or plasma and/or fire polishing is performed on rod. The tube is made of fluorine doped quartz glass. A single block and/or a rotationally symmetrical substrate having a cladding tube with desired refractive index is embraced. An intermediate and/or barrier layer located on inner or outer surface is removed. An inner diameter of casing tube (1) or single block is changed by inflation, compression and/or expansion process.

Description

The invention relates to a method for producing a semifinished product for producing a bending-optimized optical fiber according to claim 1 and an optical fiber made of the semifinished product.

Bending-optimized optical fibers have a bending behavior which is matched to the respective application angle, in particular a bending sensitivity adapted thereto with respect to their optical conductivity. This applies, on the one hand, to optical fibers which are intended to exhibit a particularly pronounced flexural sensitivity, such as, for example, sensor fibers in optical bending sensor arrangements and optical fibers, which are to be as little as possible sensitive to bending, such as, for example, optical fibers required for transmitting data with a high bandwidth.

Such optical fibers have a cross section with a structured refractive index profile. This applies in particular to trench structures, graduations or even complicated combinations of several trenches of different widths and intervening refractive index-increased webs. Such fibers are treated by conventional means, i. H. the known chemical and / or physical deposition process very complicated to manufacture, the Brechzahlverläufe are quite accurately adjustable in one fiber, but the conversion to a different refractive index often requires major changes in en production runs, because while the Abscheideparameter changed in part fundamentally Need to become.

It is therefore an object to provide an economical and effective method for producing a semifinished product for producing the bending-optimized fiber, wherein the required refractive index profile can be both exactly plannable and manufactured with a minimized amount of time.

The object is achieved by a method for producing a semifinished product for producing a bending-optimized optical fiber having the features of claim 1. The subclaims contain expedient embodiments and designs of the method.

The method for producing a semifinished product for producing a bending-optimized optical fiber in application of a convergent production process from partial production of individual components. At least two individual modules are assembled at the end of the convergent production process to form the semifinished product. Each partial production of the respective individual component contains at least one of the following partial production steps carried out on a casing tube with a lower mantle number compared to the light-guiding core:
Performing a partial manufacturing step comprises applying at least one protective, intermediate and / or barrier layer on an inner and / or outer surface of the jacket tube.

Performing another part-manufacturing step comprises an outer and / or inner deposition of preferably light-guiding layers on the inner and / or outer surface of the jacket tube.

Performing a further part-fabrication step involves at least partially collapsing the coated or uncoated jacket tube into a capillary or rod.

In a part manufacturing step, a surrounding of the individual module and / or a rotationally symmetrical substrate with at least one cladding tube with a desired refractive index is provided.

A further partial manufacturing step comprises removing a protective, intermediate and / or barrier layer arranged on the inner surface in at least one individual component.

Executing a further partial production step comprises removing a protective layer, intermediate layer and / or barrier layer arranged on the outer surface in at least one individual component.

Executing a partial manufacturing step involves a change in an inner diameter of the jacket tube or the individual component by an inflation, compression and / or stretching operation.

In a further partial manufacturing step, a change in an outer diameter of a rotationally shaped rod and / or tube and / or of the individual component is carried out by an upsetting or stretching process.

In another partial manufacturing step, a heat and / or tempering treatment and / or a plasma and / or Feuerpolitur is included.

The production of the semifinished product is designed as a convergent production process. This means that the semi-finished product is prefabricated in the form of individual components, the individual components or a series of jacket pipes, initially in the form of individual components. These individual components can be processed and pre-assembled in virtually any way. As a result, in particular individual sections of the later desired refractive index profile can be generated very accurately. The individual components are then joined together, ma W. the individual part production thus converge to a final manufacturing step and the semifinished product for the production of the optical fiber is thus formed. The individual part production thus occur independently of each other and end up in a final step only at the end.

In a first expedient partial production, the following partial production steps are carried out:
First, a partial manufacturing step is carried out, in which the protective, intermediate and / or barrier layer in the form of a quartz glass layer is applied to the outer surface of the jacket tube.

Thereafter, a partial production step is carried out, in which an internal deposition of germanium and / or phosphorus-doped quartz glass takes place on the inner surface of the jacket tube.

In a further part-production step, a collapse then takes place to form a massive core rod. This is followed by a plasma polishing on the massive core rod. The individual component created in this way is combined with a covering tube made of quartz glass to form the finished semifinished product.

After the said step of the plasma polishing, the outer protective layer can be removed with a suitable modification of the partial production steps. This is followed by a unification of the individual module thus created with a casing tube made of quartz glass to the finished semifinished product.

After the above-mentioned step of the plasma polishing, with a suitable modification of the partial production steps, at least one further outer coating with doped and / or undoped quartz glass can subsequently be carried out with the aid of a plasma coating.

The mentioned partial productions can be carried out without any time delay in parallel with each other, whereby the individual components generated are finally combined.

In a first embodiment, the jacket tube is provided in the form of a fluorine-doped quartz glass tube. As a result, a refractive index reduction in the material of the jacket tube is achieved.

In a preferred embodiment, a fluorine-doped layer of desired thickness and refractive index is deposited on an undoped quartz glass tube, to which, in turn, a coating with undoped quartz glass takes place as a protective layer.

In a further expedient embodiment, the structure of the light-guiding layers is carried out by means of a CVD and / or plasma process and / or a flame pyrolysis.

The protective, intermediate and / or barrier layer is preferably made of a quartz glass with a higher melting point compared to the melting point of the material of the jacket tube. As a result, an increased stability of the semi-finished product can be achieved and ovalities and eccentricities in the structure are reduced.

The protective, intermediate and / or barrier layer expediently has a diffusion-preventing blocking function with respect to volatile glass constituents, in particular dopants which modify the refractive index and / or, in particular, fluorine. As a result, the refractive index profile is stabilized and can optionally be modified in further production steps still at a given time.

At the same time, the protective, intermediate and / or barrier layer can fulfill a further function. The protective, intermediate and / or barrier layer has, in an expedient embodiment, a chemical composition which, when the semifinished product is applied to a further substrate, the thermal, physical and / or chemical differences between the semifinished product and the further substrate, in particular the differences the thermal expansion coefficient and / or the different chemical compositions minimized. As a result, the voltages in the resulting overall system are minimized or set to an appropriate size.

After the structure of the light-conducting layers, a deposition of at least one further inner and / or outer protective, intermediate and / or barrier layer can be carried out. As a result, the modified casing pipe is prepared either inside or outside or on both sides accordingly.

In an expedient refinement, with the aid of at least one pressure regulating system, a targeted setting of an ambient pressure and / or a pipe internal pressure takes place on the jacket pipe.

Subsequently, in a useful continuation of the embodiment, a collapse to a solid rod or a capillary takes place.

In connection with this, in another continuation after the construction of the light-guiding layers, a collapse of the jacket tube occurs on another substrate. The further substrate may be either a solid rod or another jacket tube.

In an expedient embodiment of the method takes place after the construction of light-guiding layers a partial or complete collapse process to a capillary or a solid rod. After the partial or complete collapse process, mechanical processing can be added to a polygon rod.

The collapsing processes can also take place successively. In one embodiment, a subsequent Aufkollabieren at least one further doped and / or undoped jacket tube or semi-finished product. In this case, the chemical composition of at least one dopant of each individual substrate can have a constant, linear and / or gradual course in a collapsed sputtered tubular casing or semi-finished product. By such a procedure, different refractive index profiles, in particular trenches, graduations or contant sections, are added radially outwards and combined with one another.

This production can be combined with at least one further outer coating.

It is advantageous to combine in the collapsing processes glasses of the same or similar chemical composition. This increases the yield of the process step.

In a final manufacturing step, at least one of the protective, intermediate and / or barrier layers can be at least partially removed again. As a result, diffusion processes can be induced within the internal structure with which further modifications of the refractive index profile can be achieved.

The mentioned production steps can be combined with surface treatments. In an intermediate step and / or a final manufacturing step, a surface treatment, preferably a plasma and / or Feuerpolitur is thus expediently carried out.

The method will now be explained in more detail with reference to exemplary embodiments. To clarify serve the 1 and 2 , The same reference numbers are used for identical or equivalent parts.

It shows:

1 a series of exemplary processing steps on a jacket pipe,

2 the joining of several jacket tubes and a solid rod to form a semi-finished product for the production of light guides,

3 an advantageous embodiment of a jacket tube,

4 a further advantageous embodiment of a jacket tube.

1 shows a series of exemplary processing and manufacturing steps of a jacket tube 1 , The jacket tube forms the starting point for a single module or the partial production steps carried out on this single module. These can be modified with other modules produced in parallel at the same time.

The jacket tube consists in the present example of a quartz glass tube of a certain thickness. The quartz glass is provided with one or more refractive index-changing dopants. In this case, in particular fluorine, fluorine compounds, germanium, phosphorus, aluminum, boron or other halogens and their compounds and other substances can be used. The refractive index of the jacket tube is set so that it is smaller than a core refractive index of the subsequent light guide.

The jacket tube serves as a carrier for the coatings and surface modifications of the single component executed in the next steps. In a first step is on the inner and / or outer surface 2 . 4 of the jacket tube at least one protective, intermediate and barrier layer 3 applied. This layer is substantially impermeable to the doping present within the jacket tube and, after the coating process, covers the inner surface of the jacket tube uniformly. It prevents outdiffusion of the refractive index changing dopants from the quartz glass matrix of the jacket tube during the next part manufacturing steps.

To carry out the coating, the known coating methods can be used. This applies in particular to wet-chemical dipping processes, but especially to vapor and gas phase separation processes known as chemical vapor deposition CVD. In the case of wet-chemical coating processes, the jacket tube is either brought completely into a dipping bath or it is flushed through by the separating solution in the interior. To carry out the CVD method, the jacket tube is locally heated from the outside and flows through a gas stream in the interior. The gas stream contains the substance constituents intended for the layer to be applied in finely distributed form. These settle thermophoretically at the externally locally heated point of the jacket tube. To coat the entire inner surface of the jacket tube, the point of local heating in the longitudinal direction of the jacket tube is now shifted, so that a uniform inner coating with the protective, intermediate and barrier layer 3 is reached. The protection, intermediate and Barrier layer is preferably made of quartz glass with a melting point which is above that of the jacket tube. As a result, the barrier layer exerts an additional stabilizing function.

Furthermore, the protective, intermediate and barrier layer, which is arranged both inside and outside, serves 3 as a primer and / or as a compensating interlayer, the differences between the coefficients of expansion of the material of the jacket tube on the one hand and on the protective, intermediate and barrier layer 3 minimized following layers.

The jacket tube thus modified with the protective layer is now available for further coating operations to be carried out on its inner or outer surface. In the present example, the jacket tube is on the inside with a light-guiding coating 6 Mistake. The light-guiding coating may be doped with germanium. This serves as the starting structure for the light-guiding structure within the later light guide. For the inner as well as the outer coating, in principle the same coating methods can be used, which are also used for inner coating of the jacket tube.

Parallel to the first individual module described above, further individual components, in particular a second and a third individual component, and a core doped with germanium are manufactured.

The individual blocks differ from the first single block in their coating sequence. The second single module consists of a fluorine-doped jacket tube, which is provided on the outside with a protective, intermediate and barrier layer and on its inside with a germanium-doped coating.

The third single module consists of a likewise doped with fluorine jacket tube containing only on the inner surface of a protective, intermediate and barrier layer.

For application of an outer coating, the use of a plasma deposition method proves to be particularly useful. For this purpose, the jacket tube is brought into the flame region of a plasma torch located underneath and displaceable along the longitudinal axis of the tube and rotated about its longitudinal axis. Within the flame stream of the plasma torch, the substances intended for the outer photoconductive coating are added. These separate on the outside of the jacket tube.

Both the inside and the outside of the jacket tube can now be subjected to further coating operations. The number of coating processes is basically arbitrary. In this case, it is possible to produce complex layer structures, especially on a thermophoretic path within the jacket tube.

Depending on the intended structure of the semifinished product or of the optical waveguide to be produced therefrom, further modifications of the overall structure can now be made if necessary. In particular, it is possible here to apply a further protective, intermediate and barrier layer to the outside of the coated tube or else to machine the outer contour of the tube. This includes, in particular, incorporation of flattening, transfer of the round outer tube contour into a polygonal, in particular a uniform hexagonal, octagonal or also a square shape, or also introduction of local depressions or grooves extending in the longitudinal direction of the jacket tube. Such modifications can be made, for example, by a local etching, laser treatments or by sputtering processes.

The other manufacturing processes carried out on the jacket pipe depend on where the jacket pipe is to be inserted into the semifinished product to be manufactured. When using the jacket tube in the core region of the future semi-finished product, a Kallabierprozess can be performed on the jacket tube, wherein the jacket tube coincides to form a solid core rod. This Kallabierprozess can be controlled. In this case, set a pressure gradient between the inside and the outside of the jacket tube, which coincide the jacket tube with a controllable speed and / or to a controllable radius. The pressure gradient can be generated either by generating a negative pressure in the pipe interior or by a pressure applied from the outside.

Finally, the semifinished product is produced from a plurality of such individual building blocks and / or a rod or a capillary in a convergent production process. This means that several jacket tubes and the rod with different sizes, coatings are made parallel in time and combined in a final manufacturing process, the initially independent production steps of the individual jacket tubes finally lead to the final step, d. H. converge.

2 shows the final convergent manufacturing process for the production of the semifinished product. In the present case, there is a core rod 8th , a middle jacket tube 9 and an outside one casing pipe 10 intended. Each of the jacket tubes may have the above-described inner and / or outer coatings in various configurations and modifications. It is also possible that at least one of the jacket tubes has a deviating from the circular cross-section.

The union of the jacket tubes is carried out as a series of collapses. It serves the core rod 8th as a starting substrate. This consists of a previously collapsed jacket tube, but it can also be specified as a solid rod.

The core bar 8th and the middle jacket tube 9 are pushed together. Subsequently, the middle jacket tube is collapsed onto the core rod. This collapse process can be done either spontaneously or under controlled conditions with a set pressure gradient. Important here are either on the inside of the middle jacket tube or existing on the outside of the core rod protective, intermediate and barrier layers. These cause a voltage reduction or a voltage compensation during the collapse process.

The same collapse process now takes place between the middle casing pipe 9 and the outer jacket tube 10 , Now, the middle jacket tube collapsed with the core rod serves as a substrate for collapsing the outer jacket tube. As a result, a concentric layer structure formed by the base material of the jacket pipes on the one hand and by their inner and outer coatings of different refractive index ranges, either gradual or abruptly merge into each other and form in particular in the coatings of the jacket pipes trench or step structures that after the Pull the light guide refractive index trench structures result, which are tuned to the respective required bending sensitivity of the light guide.

The arrangement thus formed may be subjected as a whole to a plasma and / or Feuerpolitur and / or a temperature treatment, so as to achieve a tension-free and provided with a flawless surface semi-finished product.

Below, further embodiments for the preparation of the individual components and the semifinished product will be explained.

3 describes an advantageous embodiment of a jacket tube, including an inner protective layer 15 , a refraction-reduced area 16 , an undoped or doped interlayer 17 , another fractional area 18 and an outer protective layer 19 ,

4 describes an advantageous embodiment of a jacket tube, including an inner protective layer 15 , a refraction-reduced area 18 and an outer protective layer 19 , The outer diameter of the embodiments are each 30 to 40 mm, the inner diameter 25 to 35 mm.

For pipe production, an auxiliary material is provided in a first step. This is preferably a graphite or SiC rod, whereby any other heat and temperature resistant material can be used. In the example given, a graphite rod is used.

In the following, the graphite rod is exposed to the inner protective layer 15 of 1-2 mm wall thickness, preferably 1.5 mm, which either aufkollabiert in the form of a substrate tube on the graphite rod or can be formed in the course of a direct coating on the graphite rod. This inner protective layer preferably consists of undoped quartz glass, but depending on the application, it may also contain at least one dopant. Subsequently, the formation of a fluorine-doped trench occurs 18 with a wall thickness of 1.5-2.5 mm, preferably 2 mm and a refractive index reduction of Δn between -0.006 and -0.012, preferably -0.009, by means of deposition processes, wherein preferably the POVD or MCVD method or the so-called smoker is applied.

Subsequently, the application of the outer protective layer of 0.2-3 mm, preferably 1 mm, either by Aufbollabieren a tube with the desired glass composition or by direct coating with the aforementioned method.

After removal of the auxiliary material - in the present example, the graphite rod - there is a processing and / or cleaning and / or temperature treatment of the inner surface.

This procedure is followed by a stretching step, so that the outer diameter of the new tube between 24 and 36 mm is preferably 32 mm. In this tube, the light-guiding layers are deposited by means of the CVD method or the PIVD method, wherein the refractive index increases continuously from a certain number of layers. Finally, the tube thus produced is collapsed to a capillary or a solid rod.

The resulting product is after the preparation of the outer surface with at least one tube of desired refractive index and Surround wall thickness or coated in the course of a direct coating with other layers of desired refractive index and wall thickness. As a result, the correct core / sheath ratio is generated in the later optical fiber.

In the first step, the provision of an auxiliary material for pipe production, preferably a graphite or SiC rod, whereby any other heat and temperature resistant material can be used. In the example given, a graphite rod with 43 mm outer diameter is used.

In the following, the graphite rod is charged with a glass soot layer of the desired refractive index. Subsequently, the deposition of the inner protective layer takes place 15 preferably consisting of undoped quartz glass with a thickness between 0.2-1.2 mm, preferably 0.7 mm. Subsequently, the formation of a first doped trench occurs 16 with a wall thickness of 0.2-1.3 mm, preferably 0.7 mm and a refractive index change of Δn in absolute value between 0.001 and -0.005, preferably 0.0025, by means of deposition processes, wherein preferably the POVD or MCVD method or the so-called smoker is applied.

Another intermediate layer of quartz glass with a wall thickness between 0.01 mm and 2.5 mm, preferably 0.7 mm, is applied by means of the aforementioned methods, which are either undoped quartz glass or doped quartz glass, in which case whose refractive index difference Δn ₂ preferably applies: Δn ₂ = -Δn +/- 0.001

Following this intermediate layer 17 the formation of a fluorine-doped trench occurs 18 with a wall thickness of 0.3-2.5 mm, preferably 1.0 mm and a refractive index reduction of Δn between -0.006 and -0.012, preferably -0.009. The remaining steps are similar to those of the embodiment 1.

In a further embodiment, in the first step, the provision of an auxiliary material for tube production, preferably a graphite or SiC rod, wherein in this case also any other heat and temperature resistant material can be used. In the example given, a graphite rod with 43 mm outer diameter is used.

In the following, the graphite rod is charged with a glass soot layer of the desired refractive index. This is at least partially fused by subsequent coating processes to form a glass layer. Subsequently, the formation of a fluorine-doped trench occurs 18 with a wall thickness of 0.4-2.5 mm, preferably 1.5 mm and a refractive index reduction of Δn between -0.006 and -0.012, preferably -0.009, by means of deposition processes, wherein preferably the POVD or MCVD method or the so-called Smoker is applied. This tube comes with an outer protective layer 19 provided, which preferably consists of undoped quartz glass and has a wall thickness between 0.1 and 3 mm, preferably 0.5 mm.

After removal of the auxiliary material - in the present example, the graphite rod - there is a processing and / or cleaning and / or temperature treatment of the inner surface. One or more stretching processes may follow.

Subsequently, with the help of Innenabscheideprozessen, such as MCVD or PIVD (plasma inside vapor deposition), the desired refractive index sequence is produced. After completion of the inner coatings, a temperature treatment and / or stretching processes can be carried out. The product resulting therefrom is enveloped after the preparation of the outer surface with at least one tube of desired refractive index and wall thickness or coated in the course of a direct coating with further layers of desired refractive index and wall thickness. As a result, the correct core / sheath ratio is generated in the later optical fiber.

It goes without saying that the embodiments described here must be adapted in the sequence of the individual steps and coating parameters such as refractive index, wall thickness, diameter data, number of layers and sequence by the person skilled in the art in accordance with the problem to be solved.

The method has been described by means of exemplary embodiments. Further embodiments will become apparent from the dependent claims and in the context of expert action.

LIST OF REFERENCE NUMBERS

1

casing pipe

2

inside

3

Protective, intermediate and barrier layer

4

outside

5

light-guiding coating

6

inner photoconductive coating

7

outer photoconductive coating

8th

core rod

9

middle jacket pipe

10

outer jacket tube

15

inner protective layer

16

first spiked trench

17

interlayer

18

fluorine-doped trench

19

outer protective layer

Claims (20)

A method for producing a semifinished product for producing a bending-optimized optical fiber in application of a convergent production process of partial production of individual components, wherein at least two individual components are joined to the semifinished product at the end of the convergent production process, each partial production of the respective individual component at least one of the following, on a casing tube ( 1 ) comprising a partial production step (A to I) which is lower in comparison to the light-guiding core, comprises: - carrying out a partial production step (A), comprising applying at least one protective, intermediate and / or barrier layer ( 3 ) on an inner and / or outer surface ( 2 . 4 ) of the jacket tube, - carrying out a partial production step (B), comprising an outer and / or inner deposition of preferably light-guiding layers ( 5 . 6 . 7 ) on the inner and / or outer surface of the mandrel, - performing a partial manufacturing step (C) comprising at least partially collapsing the coated or uncoated mandrel into a capillary or rod, performing a part manufacturing step (D) comprising surrounding the single component and / or a rotationally symmetrical substrate having at least one cladding tube with a desired refractive index, - carrying out a partial manufacturing step (E), comprising removing a protective, intermediate and / or barrier layer arranged on the inner surface ( 3 ) in at least one individual component, - carrying out a part-production step (F), comprising removing a protective, intermediate and / or barrier layer arranged on the outer surface ( 3 ) in at least one individual component, - carrying out a partial production step (G), comprising a change in an inner diameter of the jacket tube ( 1 ) or of the individual component by an inflation, compression and / or stretching process, - carrying out a partial production step (H), comprising a change in an outer diameter of a rotating rod and / or tube and / or the individual component by an upsetting or stretching operation, - execution a partial manufacturing step (I), comprising a heat and / or tempering treatment and / or a plasma and / or Feuerpolitur. Method according to claim 1, characterized by a partial production consisting of the partial production steps (A), (B), (C), (I), wherein - when carrying out the partial production step (A) on the outer surface of the jacket tube, the protective, intermediate and / or barrier layer ( 3 ) is applied in the form of a quartz glass layer, - in which the partial production step (B) is carried out on the inner surface of the jacket tube an internal deposition of germanium and / or phosphorus doped quartz glass, - in the execution of the part manufacturing step (C) collapsing to a massive Kernstab takes place, - carried out in the execution of the partial manufacturing step (I) a Plasmapolitur on the massive core rod, and then a unification of the thus created single block is made with a surrounding quartz glass cladding tube to the finished semi-finished. Method according to claims 1 and 2, marked by a partial production consisting of the partial production steps (A), (B), (C), (F), wherein after carrying out the partial production steps (A), (B) and (C) When the partial manufacturing step (F) is carried out, a removal of the outer protective layer is carried out, and then a unification of the thus created individual block with a casing made of quartz glass covering tube to the finished semi-finished product takes place. Method according to one of the preceding claims, marked by a partial production consisting of the partial production steps (A), (B), (C), (I) and (B), wherein after the execution of the partial production steps (A), (B) and (C) In the execution of the part manufacturing step (I) a plasma polishing is carried out, - In a subsequent to the part manufacturing step (I) and executed for the second time part manufacturing step (B) at least one further outer coating with doped and / or undoped quartz glass by means of a plasma coating is performed. Method according to one of the preceding claims, characterized in that the jacket tube ( 1 ) is provided in the form of a fluorine-doped quartz glass tube. Method according to one of the preceding claims, characterized in that the structure of light-guiding layers ( 5 . 6 . 7 ) is carried out by means of a CVD and / or plasma process and / or a flame pyrolysis. Method according to one of the preceding claims, characterized in that the protective, intermediate and / or barrier layer ( 3 ) is preferably made of quartz glass with a higher melting point compared to the melting point of the material of the jacket tube. Method according to one of the preceding claims, characterized in that the protective, intermediate and / or barrier layer ( 3 ) has a diffusion-preventing barrier function with respect to glass components, in particular refractive index-reducing dopants and / or in particular fluorine. Method according to one of the preceding claims, characterized in that the protective, intermediate and / or barrier layer ( 3 ) has a chemical composition which minimizes the thermal, physical and / or chemical differences between the semifinished product and the further substrate, in particular the differences in the coefficients of thermal expansion and / or the different chemical compositions when applying the semifinished product to another substrate. Method according to one of the preceding claims, characterized in that after the structure of the light-guiding layers ( 5 . 6 . 7 ) a deposition of at least one further inner protective, intermediate and / or barrier layer ( 3 ) is performed. Method according to one of the preceding claims, characterized in that with the aid of at least one pressure control system, a targeted setting of an ambient pressure and / or an internal pipe pressure. Method according to one of the preceding claims, characterized in that after the structure of the light-guiding layers ( 5 . 6 . 7 ) Aufkollabieren the jacket tube is carried out on another substrate. Method according to one of the preceding claims, characterized in that after the structure of the light-guiding layers ( 5 . 6 . 7 ) is carried out a partial or complete Kallabierprozess to a capillary or a solid rod. Method according to one of the preceding claims, characterized in that after the partial or complete collapse process, a mechanical processing is carried out to form a polygon rod. Method according to one of the preceding claims, characterized in that a subsequent Aufkollabieren at least one further doped and / or undoped cladding tube or semi-finished, wherein in a aufkollabierten doped cladding tube or semi-finished the chemical composition of at least one dopant of each substrate radially a constant, linear and / or takes gradual course. Method according to one of the preceding claims, characterized in that at least one further outer coating is performed. Method according to one of the preceding claims, characterized in that in a final manufacturing step at least one of the protective, intermediate and / or barrier layers ( 3 ) is removed again. Method according to one of the preceding claims, characterized in that in an intermediate step and / or a final manufacturing step, a surface treatment, preferably a plasma and / or Feuerpolitur is performed. Method according to one of the preceding claims, characterized in that in the Aufkollabieren glasses of the same or similar chemical composition are combined. Optical fiber produced from a semifinished product according to one of the preceding claims.

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