Laterally emitting optical waveguides and methods for introducing micromodifications into optical waveguides - Patents.com

Abstract

A novel method for introducing micro-modification into optical waveguides is proposed. The method of introducing micromodifications into an optical waveguide according to the present invention comprises the steps of: a step of fixing an optical waveguide to a holder, the optical waveguide and / or the holder being movably supported; focusing the high-energy radiation at a focal position by a focusing device, the focal position being positionable within an optical waveguide, the high-energy radiation being generated in a pulsed mode by a radiation source, the focusing device and the optical waveguide being configured for movement between the optical waveguide and the focal position; and moving the focal position through the optical waveguide while varying the rotation speed of the optical waveguide; Includes.

Description

[Technical field]

[0001] The present invention relates to optical waveguides and methods for introducing micro-modifications into optical waveguides. [Background technology]

[0002] Optical waveguides known in the prior art usually consist of an optical waveguide core (hereinafter referred to as core) and an optical waveguide jacket (hereinafter referred to as jacket). In this case, a commonly used material is, but not limited to, quartz glass. In order to ensure loss-free transmission of light in the core, the refractive index of the jacket is smaller than that of the core. This allows total internal reflection to be used at the transition between the core and the jacket, which transmits the light in the core of the optical waveguide. The jacket may further be covered by another cladding. In addition to this, typical optical waveguides often further have so-called coatings and / or buffers that can surround the jacket. These additional layers are usually designed in such a way that they generally contribute to the mechanical stability of the optical waveguide and in particular ensure that the optical waveguide can bend well without breaking and mechanically protect it against external influences.

[0003] Usually, light entering the core on one side and being guided through the core almost losslessly leaves the optical waveguide at the other end of the optical waveguide. In order to change the optical path of the light in the core, it is known to introduce modifications into the material of the core or into the boundary region between the core and the jacket. By diffraction and / or scattering and / or refraction of the light at this modification, which can be described as a disturbance, the optical path can be changed in such a way that a precise lateral exit of at least the amount of light transmitted in the core of the optical waveguide is achieved. If the provided modifications are introduced over a certain section along the core and / or the boundary region between the core and the jacket, the lateral exit can likewise take place over this certain section.

[0004] These processed regions can be used as so-called fiber applicators, which are usually formed at one end of the light guide or in the middle of the light guide. It is also known to realize these so-called fiber applicators by means of attachments which are attached substantially from the outside. For example, watertight closed attachments are known which are attached to the light guide at one end of the light guide. In this case, mechanically and / or chemically roughened ends of the light guide or a liquid mixed with scattering particles is used to change the light path so that the light is emitted laterally, which liquid circulates in a liquid-tightly formed attachment. Applicators of this kind are known, for example, from US Pat. No. 5,399,623, US Pat. No. 5,399,623 or US Pat. No. 5,399,623.

[0005] Yet another type of such mounted applicator, as known for example from US Pat. No. 5,399,633, US Pat. No. 5,499,667 or US Pat. No. 5,499,677, is a mount formed as a hollow body attached to one end of an optical waveguide, which is then filled with a support matrix, for example a silicone gel, containing particles used as scattering centers, the density of the scattering particles then being either uniformly distributed or increasing continuously towards the end.

[0006] Such mounted fiber applicators are mostly made of polymeric materials and therefore can withstand elastic and mechanical loads well, but they also have crucial disadvantages due to the fact that they are essentially a two-piece construction of the optical waveguide and the mounted applicator. For example, the thermal load resistance of the mounted applicator is usually much lower than that of the optical waveguide. In the case of such applicators, there is also the risk of them detaching from the optical waveguide. Different manufacturers of such mounted applicators usually use different materials, which results in correspondingly different thermal and mechanical properties of the applicators, which are only suitable for certain wavelengths and powers. This makes it very difficult to exchange between different applicators, all the more because these fiber applicators are optimized for specific applications. Yet another crucial disadvantage of mounted applicators is their manufacturing process. The assembly is usually done by hand and is not automated due to its complexity. In addition, air bubbles or foreign objects may be trapped during manufacturing, which can cause excessive light refraction and create undesirable so-called hot spots, resulting in a relatively high rejection rate.

[0007] In the patent application WO 02 / 04336, a method is described for introducing modifications into transparent materials using focused laser radiation. In this case, laser pulses in the nanosecond range are used to generate microcracks in the transparent material, which can be used as light scattering centers. When transferring this method to the use in optical waveguides, it is precisely these microcracks thus generated that are problematic, since such cracks would lead to material weakening in the optical waveguide, which could damage or even break the optical waveguide when subjected to thermal or mechanical loads, for example when the optical waveguide is bent. Furthermore, such microcracks are not controllable in size and orientation relative to the optical waveguide axis.

[0008] From US Pat. No. 5,399,433 a method is known for introducing micromodifications into an optical waveguide, which serve as scattering centers. The process parameters, such as the pulse duration of the laser radiation used, are not detailed therein, so that the detailed nature of the resulting micromodifications is unclear. However, the detailed shape has a decisive influence on the emission and mechanical stability of the optical waveguide.

[0009] Similarly, from Patent Document 9, a laser applicator is known, which comprises an optical waveguide having scattering means suitable for at least partially scattering the light transmitted therethrough out of the core of the optical waveguide, at least some of the scattering centers forming a diffraction grating. Although a method suitable for introducing scattering centers into the optical waveguide is disclosed, detailed settings of parameters necessary for precisely controlling the properties of the scattering centers are not described.

[0010] In US Pat. No. 5,399,633 a method for microstructuring optical waveguides using ultrashort laser pulses is described. This method, and others mentioned above, are generally described both in terms of the microstructures and in terms of the optical waveguides to be fabricated, including descriptions of the shape, size and distribution / arrangement of the fabricated microstructures, but without mentioning any particular morphology taking into account thermal and mechanical stability.

[0011] It is known that mechanical failures (fracture of the optical waveguide) can occur if the optical waveguide is bent or subjected to other loads (e.g. mechanical and / or thermal) and the stresses generated inside the optical waveguide have an excessive effect on the mechanical stability. Microcracks can occur in the outer region of the optical waveguide jacket already during the manufacturing process, in particular during the drawing process. Due to the mechanical connection of the coating (and / or buffer) with the jacket surface of the jacket, the stresses thus generated can be guided away so that they are not amplified (so-called crack propagation) and therefore the mechanical stability of the optical waveguide is also not impaired. Furthermore, there is a known problem that further processing of the interior of the optical waveguide, for example of the core or the jacket, reduces the mechanical stability of the optical waveguide. Stresses that are still tolerable in the raw optical waveguide can thereby propagate cracks in the processed optical waveguide, which can lead to the failure of the optical waveguide. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] German Patent No. 4137983 [Patent Document 2] DE 4211526 A1 [Patent Document 3] DE 4316176 A1 [Patent Document 4] DE 10129029 A1 [Patent Document 5] U.S. Pat. No. 4,660,925 [Patent Document 6] U.S. Patent No. 5,196,005 [Patent Document 7] DE 4407547 A1 [Patent Document 8] DE 19739456 A1 [Patent Document 9] European Patent No. 1342487 [Patent Document 10] International Publication No. 2004 / 005982 [Patent Document 11] US Patent Application Publication No. 2008 / 0158905 [Patent Document 12] US Patent Publication No. 06832023 [Patent Document 13] JP 2006-285234 A Summary of the Invention [Problem to be solved by the invention]

[0013] The object of the present invention is to avoid or reduce one or more of the disadvantages of the prior art. In particular, the object of the present invention is to provide an optical waveguide that is suitable for at least partially emitting the light guided therein to the sides and at the same time has the highest possible mechanical stability. Furthermore, the object of the present invention is to provide a method for introducing micromodifications into an optical waveguide that are suitable for emitting at least some part of the light propagating inside the optical waveguide to the sides. [Means for solving the problem]

[0014] The above problem is solved starting from an optical waveguide as defined in the preamble of claim 1 by the features defined in the characterizing part of claim 1 and by the features of a method for introducing micromodifications as defined in claim 11.

[0015] The optical waveguide according to the invention comprises an optical waveguide core and a region at the distal end of the optical waveguide, in which micromodifications are arranged, the arrangement of the micromodifications being ordered. In contrast to a non-ordered or chaotic distribution, an ordered distribution of the micromodifications makes it possible to control the stress distribution and the emission geometry in the optical waveguide. In the case of a non-ordered distribution, it may happen that in the region of the peak stress, another micromodification is arranged, which further increases the stress. This would then necessarily cause a mechanical weakening of this region, which may damage the optical waveguide. If the micromodifications are introduced in an ordered manner, the stress distribution can be actively controlled. This allows the micromodifications to distribute the mechanical loads, so that the optical waveguide can be subjected to higher mechanical loads during operation before failure, compared to optical waveguides with a random distribution of micromodifications. Furthermore, the correct alignment of the micromodifications allows for shorter processing times, since the micromodifications are introduced only where they contribute effectively to the lateral emission of the light transmitted in the optical waveguide. This cannot be guaranteed if the distribution of the micromodifications is not ordered. Therefore, if the distribution of the micromodifications is not ordered, more micromodifications must be introduced to achieve the same lateral emission intensity than if the arrangement of the micromodifications is ordered.

[0016] In a preferred embodiment of the optical waveguide, the micro-modifications are arranged on one or more parallel cut planes, where a first cut plane is located perpendicular to the optical waveguide axis, and the arrangement of the micro-modifications on the first cut plane is determined by one or more parameters selected from the group of parameters including symmetrical arrangement of the micro-modifications, density of the micro-modifications on the first cut plane, density of the micro-modifications, size of the micro-modifications, distance of the micro-modifications to the optical waveguide axis, mutual spacing of the micro-modifications, orientation of the micro-modifications, or other parameters used to describe the location and distribution of the micro-modifications, or size or shape of the micro-modifications.

[0017] In yet another preferred embodiment of the optical waveguide, the sequence of micro-modifications on the first cut surface is repeated on at least one further cut surface, which has the advantage that the processing procedure can be repeated and the stress distribution provided by a particular sequence of micro-modifications can be continued over a relatively long area.

[0018] In yet another particularly preferred embodiment of the optical waveguide, at least one further cut plane in which the sequence of micro-modifications on the first cut plane is repeated is rotated by an angle relative to the first cut plane.

[0019] In yet another particularly preferred embodiment of the optical waveguide, the distance between the first cut surface and at least one further cut surface, in which the sequence of micro-modifications is repeated, is greater than the extent of a single micro-modification.

[0020] In yet another embodiment of the invention, the distance between a first cut surface and at least one further cut surface in which the array of micro-modifications is repeated is smaller than the extent of the micro-modifications in the axial direction of the optical waveguide, as long as the micro-modifications do not overlap or impede beam passage.

[0021] In yet another particularly preferred embodiment of the optical waveguide, at least one further cut surface having micro-modifications with a different arrangement than that of the first cut surface is located between the first cut surface and at least one further cut surface in which the arrangement of the micro-modifications of the first cut surface is repeated.

[0022] In yet another particularly preferred embodiment of the light guide, the micro-modifications on the first cross-sectional surface are arranged rotationally symmetrically around the light guide axis.

[0023] In yet another particularly preferred embodiment of the light guide, the micro-modifications are arranged on a hollow cone, the long axis of which lies on the light guide axis.

[0024] In yet another particularly preferred embodiment of the light guide, the micromodifications are arranged on a number of hollow cones, the hollow cones having different diameters and the major axes of the hollow cones being located on the light guide axis. The micromodifications do not have to occupy the entire area up to the apex of the cone, thereby forming in particular truncated or spiral cones.

[0025] In yet another particularly preferred embodiment of the light guide, the region of the distal end of the light guide in the direction of the light guide axis is divided into two sections, a first of the two sections facing towards the distal end of the light guide and a second section facing away from the distal end of the light guide.

[0026] Similarly, in yet another particularly preferred embodiment, the processed region of the optical waveguide is divided into at least two sections in which differently ordered micro-modifications are introduced with different orientations and embodiments.

[0027] The method of introducing micro-modifications into an optical waveguide according to the present invention comprises the steps of fixing the optical waveguide to one or more holders, the optical waveguide and / or the holder being movably supported; focusing high-energy laser radiation at a focal position by a focusing device, the focal position being positionable inside the optical waveguide, the radiation being generated in pulsed mode by a radiation source, the focusing device for focusing the high-energy radiation being movably supported; and moving the focal position through the optical waveguide, the movement of the focal position inside the optical waveguide being appropriately selected depending on the repetition rate to generate a predetermined array of micro-modifications.

[0028] The method of introducing micro-modifications into an optical waveguide preferably includes subjecting the optical waveguide to a motion in the form of a rotational motion.

[0029] In a preferred embodiment of the method for introducing micro-modifications into an optical waveguide, the focal position is moved continuously through the optical waveguide.

[0030] In yet another preferred embodiment of the method for introducing micro-modifications into an optical waveguide, the movement of the focal position through the optical waveguide comprises a combination of a rotational movement and one or more translational movements.

[0031] In yet another preferred embodiment of the method for introducing micro-modifications into an optical waveguide, the movement of the focal position is correlated with the repetition frequency such that an ordered, uniform or regularly varying array of micro-modifications is produced in the optical waveguide.

[0032] In yet another particularly preferred embodiment of the method for introducing micro-modifications into an optical waveguide, the arrangement of the micro-modifications is determined by one or more parameters selected from the group of parameters including the symmetrical arrangement of the micro-modifications, the density of the micro-modifications on the cut surface, the size of the micro-modifications, the distance of the micro-modifications to the optical waveguide axis, the spacing of the micro-modifications relative to each other, the orientation of the micro-modifications, or any other parameter used to describe the position and distribution of the micro-modifications, or the size or shape of the micro-modifications.

[0033] In yet another particularly preferred embodiment of the method for introducing micromodifications into an optical waveguide, the direction of incidence of the radiation into the optical waveguide is such that the optical waveguide axis and the direction of incidence form an angle not equal to 90°, in a preferred range an angle not equal to 90°+ / -5°, in a particularly preferred range an angle not equal to 90°+ / -10°.

[0034] In yet another particularly preferred embodiment of the method for introducing micro-modifications into an optical waveguide, the light collector is additionally vibrated laterally and transversely.

[0035] In the method of introducing micro-modifications, a laser system capable of generating ultrashort laser pulses is preferably used. In this case, the pulse length is preferably in the range of 0.01 to 1000 ps, ​​particularly preferably in the range of 0.05 to 10 ps, ​​and extremely preferably in the range of 50 to 500 fs. The wavelength used ranges from the visible infrared region to the near infrared region, and is preferably 300 to 1500 nm, particularly preferably 500 to 532 nm or 1000 to 1064 nm. In this case, the range of single pulse energy used is preferably 1 μJ to 100 μJ, particularly preferably 1 to 50 μJ. As a result, the power density in the focal region is 1012 to 1015 W / cm2.

[0036] The repetition rate of the laser system used or achievable is decisive in determining the processing speed when introducing micromodifications into the optical waveguide. The higher the repetition rate, the faster the light collector can be moved between the intervals of the micromodification. That is to say, high repetition rates are basically preferred. However, care must still be taken that the processing axis can be moved correspondingly quickly and precisely. Furthermore, at very high repetition rates of 1 MHz and above, heat can accumulate inside the optical waveguide, since the energy absorbed in the irradiated volume of the optical waveguide can no longer be removed quickly enough. Such heat accumulation can lead to stress cracks, which can cause the optical waveguide to become mechanically unstable or even to be destroyed. The repetition rate is therefore preferably selected in the range from 1 kHz to 1 MHz, particularly preferably in the range from 1 to 100 kHz.

[0037] The use of ultrashort light pulses (pulse duration ≦10 ps) has the advantage that the area of ​​influence of the captured thermal energy remains very small, thereby allowing the introduction of spatially limited micromodifications without damaging the surrounding material. If laser pulses in the nanosecond range are used, the energy of a single pulse is released into the ionic lattice of the irradiated material. This then leads to a heat accumulation in the irradiated material volume, just as in the case of excessive repetition rates, forming microscopic stress cracks that can well be in the millimeter range. Such damage to the material of the optical waveguide can reduce its mechanical stability to the point of possible failure of the optical waveguide under mechanical and / or thermal loads.

[0038] The use of ultrashort laser pulses allows precise changes of material properties in only an irradiated area of ​​a few micrometers, without undesirably damaging the surrounding area. In this case, the pulse width is not sufficient to release energy into the ionic lattice of the surrounding material, and heat accumulation does not occur or is much reduced. Thus, very small structures can be produced when the stress in the surrounding material is very small. The smallest possible structures and the smallest possible stresses are necessary conditions for the precise introduction of micromodifications in optical waveguides. Only then is precise structuring of the optical waveguide material possible without having to guarantee the mechanical stability of the optical waveguide.

[0039] For the method of introducing micromodifications into an optical waveguide, a device is provided that comprises an axis system and a motor system. This device is used to hold the optical waveguide, while it allows the optical waveguide to be precisely moved and rotated and allows the focal point of a laser system to be freely positioned within the optical waveguide. The method according to the invention and the associated device according to the invention allow the shape, distribution and position of the micromodifications in the optical waveguide to be freely changed. For example, the position or shape of the micromodifications can be precisely influenced by the movement speed of the linear and rotary axes or by changing the repetition frequency. For example, the distribution of the micromodifications can be precisely controlled by so-called "pulse picking" inside the laser or by a programmable shutter. The depth of the micromodifications relative to the surface of the optical waveguide envelope can be precisely influenced by precisely moving the focal point by precisely setting the focusing device. Furthermore, the depth range of the individual micro-modifications can also be influenced precisely by the corresponding selection of the single pulse energy, the pulse width, the number of pulses (single pulse, double pulse, multiple pulse), the spatial and / or temporal intervals, or even by "pulse tailoring". It is also possible to introduce micro-modifications into the optical waveguide on the side opposite the laser system by focusing through the center of the optical waveguide. In this case, it is possible to additionally use the lens-like effect of the curved surface of the optical waveguide for focusing, to generate micro-modifications with an even shorter depth range. The focal position or positioning of the focusing device relative to the optical waveguide axis also influences the alignment of the micro-modifications. Thus, the orientation of the micro-modifications can be controlled by shifting the incidence position from the perpendicular direction to the optical waveguide axis.

[0040] Any parameter that can describe the micro-modification, such as the depth position, spatial extent, distribution, mutual spacing, position, orientation or shape of the micro-modification, can affect the mechanical stability of the optical waveguide. The smaller the spatial extent of the micro-modification and the greater the mutual spacing of the micro-modifications, the less the influence on the mechanical stability of the optical waveguide. However, on the other hand, the light output intensity caused by the micro-modifications behaves substantially oppositely to the influence on the mechanical stability. Therefore, a compromise between the output light intensity and the mechanical or thermal stability of the optical waveguide is essential.

[0041] Several embodiments are conceivable regarding the distribution of the micromodifications. For example, it is possible to intentionally generate an irregular distribution of the micromodifications in order to avoid grating effects, such as interference, and at the same time to ensure a uniform distribution of the emitted light. On the other hand, precise uniform or periodic distributions of the micromodifications, such as Bragg gratings or multidimensional photonic structures, are also conceivable. Furthermore, it is possible to place the micromodifications densely inside the waveguide, so that they form lines that even have waveguiding properties. The line structures can be designed to have any length and the extension of the line structures relative to the optical waveguide can also be designed to be any, for example linear or spiral or helical.

[0042] The above mentioned processing possibilities are not limited to a specific type of optical waveguide: by appropriately adjusting the processing parameters, it is possible to process any type of optical waveguide, for example hollow fibers, gradient index fibers, new high-tech lead-free glass fibers, photonic crystals or photonic crystal fibers. [Brief description of the drawings]

[0043] [Figure 1] 1 is a schematic structure of an optical waveguide having micro-modifications induced by laser radiation. [Diagram 2] 1 is a schematic diagram of an optical waveguide and the incidence of focused laser light, and the possibility of relative motion between the focused laser light and the optical waveguide. [Diagram 3] 1A and 1B show a schematic structure of a processing device for processing an optical waveguide, where FIG. [Figure 4] This is a method for processing optical waveguides by laser radiation. [Diagram 5] 1 shows a schematic structure of an optical waveguide having micro-modification induced by laser radiation, where a) is the optical waveguide and b) is a cross-section along the cutting lines AA, BB, CC, DD, and EE of the schematic structure of an optical waveguide having micro-modification induced by laser radiation. [Figure 6] 1 shows a schematic structure of an optical waveguide having micro-modification induced by laser radiation, where a) is the optical waveguide and b) is a cross-section along the cutting lines AA, BB, CC, DD, and EE of the schematic structure of an optical waveguide having micro-modification induced by laser radiation. [Figure 7] 1 shows a schematic structure of an optical waveguide having micro-modification induced by laser radiation, where a) is the optical waveguide and b) is a cross-section along the cutting lines AA, BB, CC, DD, and EE of the schematic structure of an optical waveguide having micro-modification induced by laser radiation. [Figure 8]a) is a cross-section along the cutting line AA of the schematic structure of an optical waveguide having micro-modification induced by laser radiation; b) is a cross-section along the cutting line BB of the schematic structure of an optical waveguide having micro-modification induced by laser radiation; c) is a cross-section along the cutting line CC of the schematic structure of an optical waveguide having micro-modification induced by laser radiation; d) is a cross-section along the cutting line DD of the schematic structure of an optical waveguide having micro-modification induced by laser radiation; e) is a cross-section along the cutting line EE of the schematic structure of an optical waveguide having micro-modification induced by laser radiation; f) is a cross-section along the optical waveguide axis of the schematic structure of an optical waveguide having micro-modification induced by laser radiation. [Figure 9] a) is a periodic sequence of a schematic structure of an optical waveguide having micro-modification induced by laser radiation; b) is a periodic sequence of a schematic structure of an optical waveguide having micro-modification induced by laser radiation; c) is a periodic sequence of a schematic structure of an optical waveguide having micro-modification induced by laser radiation. [Figure 10] a) is a sequence of cross-sections having different distributions and / or arrangements of micro-modifications of a schematic structure of an optical waveguide having micro-modifications induced by laser radiation, and b) is a periodic sequence of regions having the same sequence of cross-sections having different distributions and / or arrangements of micro-modifications of a schematic structure of an optical waveguide having micro-modifications induced by laser radiation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The present invention will now be described in detail with reference to several examples.

[0045] FIG. 1 shows a schematic diagram of an optical waveguide (1) to be processed. The optical waveguide comprises a first region (15) which is almost free of micromodifications (5) and a second region (16) of the optical waveguide (1) where micromodifications (5) are introduced. This region (16) is often located at the distal end of the optical waveguide (1). Optionally, the optical waveguide may comprise an end cap (14) which prevents light from exiting the end region of the optical waveguide (1). This end cap (14) reflects the light waves and thereby makes them available again for lateral exit by micromodification. Instead of the end cap (14), a suitable direct mirror polishing of the fiber end face may also be used, which is also in accordance with the invention. The core (11) is surrounded by a jacket (12) followed by a coating and / or a buffer (13). The core (11) and the jacket (12) are usually made of quartz and are differently doped. The refractive index of the jacket material is smaller than that of the core material, so that the light can be transported by total internal reflection at the transition between the core and the jacket of the optical waveguide (1). The jacket (12) is surrounded by a so-called coating and / or buffer (13), which absorbs stresses when the optical waveguide (1) is bent, thus ensuring a fracture-free bending and serving to protect the underlying layers against mechanical influences. To process the optical waveguide (1), the buffer (13), which is non-transparent to the selected laser wavelength, can be removed. The laser light then only needs to be focused through the jacket (12). In the case of a buffer material, such as nylon or PTFE, which is transparent to the selected laser wavelength, the optical waveguide (1) can be processed through the buffer (13). This has the advantage that the region of the optical waveguide (1) that is processed has substantially the same bending stiffness as the remainder of the optical waveguide (1).

[0046] Similarly, in FIG. 2, the principle of the injection of focused laser light (2) into an optical waveguide (1) in order to introduce a micro-modification (5) is shown. FIG. 2 shows the focusing optics (21) required to focus a laser pulse in the core region of the optical waveguide (1) and the generated micro-modification (5). In this case, the lens parameters important for the introduction of a micro-modification (5) into the optical waveguide (1) are the focal length and the numerical aperture (NA) of the focusing optics (21), which are symbolically shown. The focal length is chosen as short as possible, since this allows the size of the focal spot to be minimized. However, the focal length must then be long enough to allow focusing through the optical waveguide jacket into the core (11). In a preferred variant, the focal length of the focusing optics (21) is between 1 and 5 mm. However, the use of “long-distance” microscope objectives with a working distance larger than 5 mm is also a preferred realization option. It is also advantageous that the NA of the focusing optics (21) is as large as possible, since this determines the aperture angle of the focusing optics (21). The larger the aperture angle, the shorter the focal region. This is very important, since this allows the depth range of the introduced modifications (5) to be minimized. With a larger aperture angle, the diverging ray bundle becomes larger, which causes the beam diameter to increase sharply before and after the focal point. This reduces the energy density in the regions before and after the focal point and therefore also reduces the absorption and the risk of damage outside the focal region.

[0047] In one particularly preferred variant, an aspheric lens with a short focal length (f<3.1 mm) and a numerical aperture of NA>0.68 is used as the focusing optics (21). In yet another embodiment, a special objective lens (lens system) with a high NA is used. It is designed in such a way that the wavefront of the focused laser radiation (22) has the same radius of curvature as the material surface on which this laser radiation strikes. This has the advantage that it does not distort the wavefront (wave front distortion) when passing through the light guide surface, which also leads to a clear improvement in the focusing at the envelope of the light guide (1).

[0048] FIG. 3 shows a principle diagram of an apparatus (20) according to the invention for introducing micromodifications into an optical waveguide. The apparatus (20) comprises different motorized adjustment devices (33, 34) for carrying out a linear movement between the optical waveguide (1) and the focal point of the focused laser beam (22). The movement is preferably performed in the spatial directions (X, Y, Z) by the linear motors (33, 34). Furthermore, the apparatus (20) comprises a structure (23) for injecting the laser light (2) into the focusing optics (24). Furthermore, the apparatus (20) comprises a holder (32) for the optical waveguide (1) and rotation axes (α, β1, β2, β3) for rotating it. In contrast to known solutions, only the optical waveguide (1) is moved, and not the focusing lens. This has the advantage that no polarizing mirrors need to be moved or moved in the optical path during processing. As a result, the alignment or adjustment of the device is much less laborious and at the same time the long-term stability of the structure is improved, since all optical elements can be fixedly installed in the optical path. Even slight inaccuracies or deviations in the optical path will change the position of the laser beam (2) on the focusing optics (24), for example when a deflection mirror is translated. As a result, the focusing point changes position in the XY plane and also in the Z direction due to the passage of an inclined (non-perpendicular) beam through the focusing optics (24) relative to the optical waveguide (1). Therefore, it is very difficult or not possible to realize a long-term stable structure with reproducible processing results.

[0049] The Z-axis (34) supports another processing structure consisting of the X-axis and Y-axis (33), the rotation device (31), and the holder / guide (32) for the light guide (1). The Z-axis is used to move the light guide (1) towards or away from the collection optics (24). In this way, the distance of the focal point from the center point of the light guide (1), i.e. the depth position, can be changed. The X-axis (33) is used to move the light guide or the holder / guide (32) along the extension of the light guide under the collection optics (24). That is, the maximum length of the modified area is determined only by the maximum path of movement of these axes. The Y-axis (33) moves the holder / guide (32) perpendicular to the extension of the light guide under the collection optics (24). The Y-axis is used for the control of the orientation of the micromodification (5). This is because the Y-axis (33) allows the focusing optics (24) and the light guide (1) to be oriented relative to one another in such a way that the laser beam (2) strikes the light guide surface as perpendicularly as possible. If the surface strikes obliquely, the distortion of the focal area changes the light path, which, in addition to influencing the orientation, also influences the shape and size of the modifications introduced. The laser beam (20) used is usually directed to the focusing optics (24) via a polarizing mirror (23), but this is not mandatory. The light guide (1) to be processed is held in a precise position in front of the focusing optics (24) by a holder and guide (32). This guide leaves the area of ​​processing free or is transparent to the laser radiation (2 or 22) used. A rotation device (31) is used to rotate the light guide (1) about its longitudinal axis. For this purpose, the light guide (1) is attached to the rotation device (31) by means of a clamping device. In that case, in order to avoid excessive torsional stress on the optical waveguide (1), the optical waveguide is always rotated only slightly, up to about 360° and then in the opposite direction up to about 360°. This can be realized both with lost optical waveguide sections, e.g. standardized optical waveguides, and also with a roll-to-roll manufacturing process, where the optical waveguide (1) can be made to any length.

[0050] In Fig. 4, a method for processing an optical waveguide (1) by means of laser radiation (2) is shown in one embodiment of the invention. First, the optical waveguide (1) is fixed in place (41) using a holder / guide (32). The holder / guide (32) is shaped so that the laser radiation (2) can reach the area of ​​the optical waveguide (1) where the micromodification is to be generated. The optical waveguide is supported so that it can be moved in three spatial directions relative to a focal position. This can be achieved by a movable optical element (24) and a fixed support of the optical waveguide (1) or by a fixed optical element (24) and a movably arranged optical waveguide (1). The movement possibilities include the three spatial directions X, Y, Z, a rotation α about the longitudinal axis of the optical waveguide (1) and / or a rotation β1, β2, β3 about one or more axes. In a further method step (42), the laser beam (2) is focused. The focused laser beam (2) is positioned such that, by means of the movable focal position, the focal position is movable throughout the area in which the micromodifications are to be introduced. The focal position is moved in a predetermined pattern (43) through the optical waveguide. A pulsed laser beam is preferably used. By continuously moving the focal position through the optical waveguide (1) at a constant speed, micromodifications (5) are generated that are equally spaced in the direction of movement. By moving the focal position in a predetermined pattern through the optical waveguide (1), more than 20 micromodifications (5) are generated. In a preferred embodiment of the invention, by moving the focal position in a predetermined pattern through the optical waveguide (1), more than 36 micromodifications (5), particularly preferably more than 360 micromodifications (5), are generated. In a further method step, the movement of the focal position is repeated in a predetermined pattern through the optical waveguide (5) (44).

[0051] In yet another advantageous embodiment, after the introduction of the micro-modifications (5) by moving the focal position through the optical waveguide (1) in a predetermined pattern has been completed, the focal position relative to the optical waveguide (1) is changed by translational and / or rotational movements.

[0052] This helps to avoid that in the repeated steps, the micro-modifications (5) introduced into the optical waveguide (1) by moving the focal position through the optical waveguide (1) in a predetermined pattern are located exactly behind, in the direction of the optical waveguide axis (17), the micro-modifications (5) introduced into the optical waveguide (1) in the first step by moving the focal position through the optical waveguide (1) in a predetermined pattern.

[0053] In another advantageous embodiment of the invention, the focal position is moved continuously through the optical waveguide (1) along the optical waveguide axis, which subsequently results in one of the above-mentioned arrangements in the cut planes, thus dividing the processing in the cut planes into steps that generate individual points at each pass along the optical waveguide axis (17).

[0054] In yet another advantageous embodiment of the invention, the successive movement of the focal position through the optical waveguide (1) in a predetermined pattern is superimposed by a further movement, which may for example be a vibration used to generate, in repeated steps, a certain lateral offset between the micro-modifications (5) introduced in the optical waveguide (1) by the movement of the focal position through the optical waveguide (1) in a predetermined pattern and the micro-modifications (5) introduced in the optical waveguide (1) in a first step by the movement of the focal position through the optical waveguide (1) in a predetermined pattern. The amplitude of the vibration is preferably at least half the distance between adjacent micro-modifications (5). Thereby an ordered arrangement of the micro-modifications in the sense of the invention is generated.

[0055] The micro-modifications (5) are arranged in the optical waveguide (1) such that when light is emitted along the optical waveguide axis (17) through the optical waveguide, the light is deflected as completely laterally as possible by the micro-modifications.

[0056] In yet another advantageous embodiment of the invention, a micromodification (5) is introduced into the optical waveguide (1) by positioning the optical axis (25) of the laser beam (2) away from the optical waveguide axis (17) during irradiation of the optical waveguide (1). In the case of a micromodification (5) whose shape differs significantly from a circular shape, i.e. having a rather elongated shape, a substantially closed surface or line of the micromodification (5) can only be achieved by a rotational movement.

[0057] In yet another advantageous embodiment of the invention, micromodifications (5) are introduced into the optical waveguide (1) by directing the optical axis (25) of the laser beam (2) at angles (β1, β2, β3) not equal to 90° onto the optical waveguide (1) during irradiation of the optical waveguide (1). In the case of micromodifications having an elongated shape, the orientation of the micromodifications (5) forms an acute angle with the optical waveguide axis (17). In yet another embodiment of the invention, the angles (β1, β2, β3) between the orientation of the micromodifications (5) and the optical waveguide axis (17) are in the range of 10° to 80°, in a preferred embodiment between 20° to 70° and in a particularly preferred embodiment between 30° to 60°.

[0058] In FIG. 5, a schematic structure of an optical waveguide with micro-modifications induced by laser radiation (partial view a)) and cross-sectional views along the cut lines AA, BB, CC, DD and EE (partial view b)) are shown. The optical waveguide (1) is composed of a core region (11) and a jacket region (12). By irradiation with the method (40) according to the invention, micro-modifications (5) are introduced into the core region (12) of the optical waveguide (1). The micro-modifications (5) on the illustrated cut planes (AA, BB, CC, DD and EE) are arranged rotationally symmetrically around the optical waveguide axis (17). The micro-modifications (5) have the same distance to the optical waveguide axis (17) on each cut plane and are arranged on a circular arc around the optical waveguide axis (17). In the section AA, the micro-modifications (5) are close to the jacket (12) of the light guide (1) and have a large distance from the light guide axis (17). In the course of the sections BB-EE, the distance of the micro-modifications (5) from the jacket (12) of the light guide (1) increases or the distance of the micro-modifications (5) from the light guide axis (17) decreases. In a further advantageous embodiment of the invention, the number of micro-modifications (5) arranged on a circular arc in the section decreases with the distance of the micro-modifications (5) from the light guide axis (17). This is achieved by varying the time interval between two laser pulses and / or the rotation speed.

[0059] In yet another advantageous embodiment of the present invention, the array of micro-modifications occurs along the entire optical waveguide in only one of the cut planes shown here (e.g., AA) or within each other in the form of multiple circles, i.e. as an array combining the cut planes shown here in one cut plane (e.g., AA with CC and / or EE).

[0060] FIG. 6 shows in a) a schematic structure of an optical waveguide with micro-modifications induced by laser radiation. In b) cross-sections are shown along the cut lines AA, BB, CC, DD and EE. The optical waveguide (1) consists of a core region (11) and a jacket region (12). In the method (40) according to the invention, micro-modifications (5) have been introduced into the core region (12) of the optical waveguide (1) by irradiation with high-energy radiation. The micro-modifications (5) on the illustrated cut planes (AA, BB, CC, DD and EE) are arranged rotationally symmetrically around the optical waveguide axis (17). The number of arrangements of micro-modifications (5) is the same on all cut planes. The arrangement of micro-modifications (5) on the cut plane BB is rotated by a certain angle around the optical waveguide axis (17) with respect to the arrangement of micro-modifications (5) on the cut plane AA. The rotation of the arrangement of the micromodifications (5) can be achieved by rotating the optical waveguide (1) between processing intervals for introducing the micromodifications (5) into the optical waveguide. In the course of the sections AA-EE, the rotation angles of the individual sections BB-EE increase relative to the section AA. In yet another advantageous embodiment of the invention, the number of sections AA-EE with different rotation angles in one processing interval is selected in such a way that the arrangement of the micromodifications (5) on the last section EE of the processing interval leads again to the arrangement of the micromodifications (5) on the first section AA of the processing interval when the rotation is continued.

[0061] In FIG. 7, a schematic structure of an optical waveguide with micro-modifications induced by laser radiation (partial view a)) and cross-sections along the cut lines AA, BB, CC, DD and EE (partial view b)) are shown. The optical waveguide (1) consists of a core region (11) and a jacket region (12). By irradiation with the method (40) according to the invention, micro-modifications (5) have been introduced into the core region (12) of the optical waveguide (1). The micro-modifications (5) on the individual cut planes (AA, BB, CC, DD and EE) are arranged rotationally symmetrically around the optical waveguide axis (17). The micro-modifications (5) are arranged on a circular arc around the optical waveguide axis (17) on the individual cut planes AA to EE. The radius of the circular arc varies over the course of the cut planes AA to EE. Furthermore, the arrangement of the micro-modifications (5) on the section BB is rotated by a certain angle about the optical waveguide axis (17) with respect to the arrangement of the micro-modifications (5) on the adjacent section AA. In order to transfer the processing steps for the arrangement of the micro-modifications (5) on the section AA to the processing steps for the arrangement of the micro-modifications (5) on the adjacent section BB, a combination of a rotation about the optical waveguide axis (17) and a translation of the focused laser beam (22) with respect to the optical waveguide (1) is possible between the processing steps of arranging the micro-modifications (5) on the adjacent sections.

[0062] In yet another advantageous embodiment of the invention, the arrangement of the micromodifications in only one of the cut planes shown here (e.g. AA) occurs along the entire optical waveguide, but rotated around the optical waveguide axis or in a combination of cut planes, i.e. in a combination of each of the cut planes shown here (e.g. AA with CC and / or EE), In yet another advantageous embodiment of the invention, the arrangement of the micromodifications occurs in a combination of cut planes, i.e. in a combination of each of the cut planes shown here (e.g. AA with CC and / or EE), but this cut plane replaces every other cut plane in the above-mentioned pattern of the individual cut planes.

[0063] FIG. 8 shows different embodiments of the invention based on a transverse section (partial view a) to (partial view e)) perpendicular to the optical waveguide axis (17) and a longitudinal section (partial view f) along the optical waveguide axis (17). In these embodiments, different forms of micro-modifications (5) induced in the optical waveguide by laser radiation are shown. Partial views a) and b) show micro-modifications (51, 52) with different sizes. The position of the micro-modifications can be selected independently. The size of the micro-modifications (51, 52) can be influenced by the size of the focal spot and / or the amount of energy introduced. The energy of a single pulse can be between 1 and 50 μJ, the micro-modifications increasing with increasing energy, depending on the material of the optical waveguide and the quality of the laser beam. Furthermore, it is possible to arrange the micro-modifications (5) such that their boundaries are in contact or overlap. The shape and positioning of the focal spot can also affect the shape of the micromodifications (52, 53). A very long focal spot will result in a micromodification (53) with an elliptical cross section with a large ratio of length to width, while a short focal spot length will result in a micromodification (52) with a small ratio of length to width. The shape of the micromodifications (53, 54, 55, 56) is another parameter that can be taken into account to generate an ordered array of micromodifications (5). In sub-figures c) to f), different longitudinal orientations of the micromodifications (53, 54, 55, 56) are shown. In sub-figure c), the micromodifications (53) are all oriented in the same direction. This is achieved when a lateral translation in the Y direction is performed between the optical waveguide (1) and the focal position between pulses of laser radiation, and the refraction resulting from the focused laser beam (22) impinging obliquely on the surface of the optical waveguide (1) is compensated for by appropriately rotating the focused laser beam (22) by β1, β2, β3.In sub-figure d), the orientation of the micromodifications (54) is arranged rotationally symmetrically around the optical waveguide axis (17) of the optical waveguide (1). This is achieved by rotating the optical waveguide (1) around the optical waveguide axis (17) between laser pulses during processing. The micromodifications (54) are oriented such that an axis along the length of the micromodifications (54) passing through the center of the micromodifications (54) intersects with the optical waveguide axis (17) of the optical waveguide (1). In sub-figure e), in addition to the processing method of sub-figure d), the arrangement and orientation of the micromodifications (5) is shown when the focused laser radiation (22) is not introduced in the direction of the optical waveguide axis (17) but the optical waveguide (1) is laterally shifted with respect to the optical waveguide axis (17). In that case, the micromodification (55) is oriented such that its longitudinal axis does not intersect with the optical waveguide axis (17) of the optical waveguide (1). Partial view f) shows a micromodification (56) in which its longitudinal axis passing through the center of the micromodification (56) forms an acute angle (γ) with the optical waveguide axis (17). The angle (γ) between the orientation of the micromodification (5) and the optical waveguide axis (17) is in the range of 10° to 80°, in a preferred embodiment in the range of 20° to 70°, in a particularly preferred embodiment in the range of 30° to 60°. The angle (γ) may be oriented such that the tip is directed towards the distal or proximal end of the optical waveguide (1). The array of micro-modifications may be formed rotationally symmetrical about the optical waveguide axis (17) and may be closer to the distal and proximal ends of the optical waveguide (1).

[0064] The movement pattern for the arrangement and / or orientation of the micromodifications (5, 51, 52, 53, 54, 55, 56) in the optical waveguide (1) has one or more movements selected from the group comprising translational movements along the spatial directions X, Y and / or Z and / or rotational movements about the optical waveguide axis (17) and / or an axis perpendicular to the optical waveguide axis (17). Within the movement pattern, at least one micromodification (5, 51, 52, 53, 54, 55, 56) is generated in the core (11) of the optical waveguide (1). Between the first execution of the movement pattern and the second and / or subsequent repetition of the execution of the movement pattern, one or more movements are performed selected from the group comprising translational movements along the spatial directions X, Y and / or Z and / or rotational movements about the optical waveguide axis (17) and / or a spatial axis. In this case, the area in which micro-modifications (5, 51, 52, 53, 54, 55, 56) are introduced into the optical waveguide (1) in the first movement pattern may overlap with the area in which micro-modifications (5, 51, 52, 53, 54, 55, 56) are introduced into the optical waveguide (1) in the second movement pattern.

[0065] FIG. 9 shows in sub-views a) to c) a schematic structure of an optical waveguide (1) with micro-modifications (5) induced by laser radiation. The indicated cut lines A, B and C characteristically represent the regions in which micro-modifications (5) have been introduced into the optical waveguide (1) as a result of the movement pattern through the optical waveguide (1) of the focal position of the focused laser beam (22). In sub-view a) a sequence of three exemplary different regions (A, B, C) of the arrangement of micro-modifications (5) is shown, which is repeated once again over the length of the optical waveguide. The number of repetitions may be several times. The regions (A, B, C) have different arrangements of micro-modifications. In that case the regions (A, B, C) are defined by one or more characteristics selected from the group including the size, number, orientation, shape and / or arrangement of the micro-modifications (5, 51, 52, 53, 54, 55, 56). The micromodifications (5, 51, 52, 53, 54, 55, 56) of each region (A, B, C) are induced by a movement pattern of the focal position and the associated irradiation of the focused laser radiation (22) through the optical waveguide (1). As a result of the different arrangements of the micromodifications (5, 51, 52, 53, 54, 55, 56), the arrangements of the micromodifications (5, 51, 52, 53, 54, 55, 56) in the regions (A, B, C) are created by different movement patterns. During the first execution of the movement pattern for creating the regions (A, B, C), one or more movements of the focal position selected from the group comprising the three spatial directions X, Y and Z, the rotation α about the long axis of the optical waveguide (1) and the rotation β1, β2, β3 about one or more axes are performed on the optical waveguide (1).

[0066] Part b) of FIG. 9 shows another sequence of regions (A, B, C) of the same arrangement of micromodifications (5, 51, 52, 53, 54, 55, 56) in an optical waveguide (1) in yet another embodiment of the invention. While there is one first region (A), there are two regions (B) with a second arrangement and three regions (C) with a third arrangement. In this fabricated optical waveguide (1), not all the regions with the micromodifications (5, 51, 52, 53, 54, 55, 56) arranged in a specific pattern occur several times.

[0067] Part c) of FIG. 9 shows another possible sequence of regions (A, B, C) of the same sequence of micromodifications (5, 51, 52, 53, 54, 55, 56). A first region (A) is followed by each region (A, B, C) that is not identical to the first region (A), while the second and third regions (B, C) alternately follow the first region (A).

[0068] Other embodiments of the invention can be shown in any mathematical sequence and order. In that case, in yet another embodiment of the invention, the optical waveguide (1) according to the invention comprises more than three regions (A, B, C) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56). In a preferred embodiment of the invention, the optical waveguide (1) comprises more than five regions (A, B, C), and in a particularly preferred embodiment, more than ten regions (A, B, C) with different arrangements of micromodifications (5, 51, 52, 53, 54, 55, 56).

[0069] Figure 10 shows in sub-view a) and sub-view b) a schematic structure of an optical waveguide (1) with micro-modifications (5, 51, 52, 53, 54, 55, 56) induced by focused laser radiation (22). In sub-view a) a sequence is shown with several regions (A, B, C, D, E, F, G, H, I, J) with different arrangements of micro-modifications (5, 51, 52, 53, 54, 55, 56). This sequence of regions (A, B, C, D, E, F, G, H, I, J) with different arrangements of micro-modifications (5, 51, 52, 53, 54, 55, 56) is repeated n times (sub-view b), where n and m are natural numbers. m represents the number of repeats of sequences in multiple regions (A, B, C, D, E, F, G, H, I, J) with different sequences of micromodifications (5, 51, 52, 53, 54, 55, 56).

[0070] In a preferred embodiment of the invention, the number of repeats of a sequence having multiple regions (A, B, C, D, E, F, G, H, I, J) with different sequences of micromodifications (5, 51, 52, 53, 54, 55, 56) is greater than 5 and in a particularly preferred embodiment greater than 20.

[0071] In yet another embodiment of the present invention, a repeating sequence having multiple regions (A, B, C, D, E, F, G, H, I, J) with different sequences of micromodifications (5, 51, 52, 53, 54, 55, 56) alternates in the orientation of the sequences.

[0072] In yet another embodiment of the invention, the repeating arrangement of a sequence having multiple regions (A, B, C, D, E, F, G, H, I, J) with different sequences of micromodifications (5, 51, 52, 53, 54, 55, 56) is in a mixed form with alternating and same directional orientations.

[0073] The following items are disclosed below: (1) An optical waveguide, an optical waveguide core; a region of the optical waveguide; and a micro-modification is provided in the region of the optical waveguide, The arrangement of the micromodifications is ordered; the micromodifications are arranged on a plurality of cut surfaces; the cut surface is positioned substantially perpendicular to a longitudinal axis of the optical waveguide; the micro-modifications on each cross section are arranged to have at least two different distances relative to the optical waveguide axis; the cut surfaces are arranged such that the micro-modifications spiral along the optical waveguide axis; An optical waveguide, wherein a distance between the micro-modifications on at least one cut surface is different from a distance between the micro-modifications on another cut surface adjacent to the one cut surface. (2) The optical waveguide described in (1), characterized in that the arrangement of the micro-modifications on the one cut surface is composed of one or more parameters selected from a group of parameters including a symmetrical arrangement of the micro-modifications, a density of the micro-modifications on the one cut surface, a size of the micro-modifications, a spacing between the micro-modifications, an orientation of the micro-modifications, or a group of other parameters used to describe the position and distribution of the micro-modifications, or the size or shape of the micro-modifications. (3) An optical waveguide as described in (1) or (2), characterized in that the arrangement of the micro-modifications on a first cut surface is repeated on at least one other cut surface. (4) The optical waveguide according to (3), characterized in that the cut surface on which the arrangement of the micro-modifications on the first cut surface is repeated is rotated by a certain angle with respect to the first cut surface. (5) The optical waveguide of (3), characterized in that the distance between the first cut surface and the other cut surface in which the arrangement of the micro-modifications is repeated is greater than the distance a single micro-modification extends within the cut surface. (6) An optical waveguide as described in any one of (3) or (4), characterized in that at least one further cut surface having micro-modifications having an arrangement different from that of the first cut surface is located between the first cut surface and the cut surface in which the arrangement of the micro-modifications of the first cut surface is repeated. (7) The optical waveguide described in any one or more of (2) to (6), characterized in that the micro-modifications on the cut surface are arranged rotationally symmetrically around the optical waveguide axis. (8) An optical waveguide according to any one or more of (1) to (7), characterized in that the region of the optical waveguide in which the micro-modifications are arranged is divided into at least two sections in the direction of the optical waveguide axis, and different orientations and embodiments of the ordered micro-modifications are introduced into the two sections. (9) 1. A method for introducing a plurality of micro-modifications into a cross-section of an optical waveguide, comprising: - fixing an optical waveguide to a holder, said optical waveguide and / or said holder being movably supported; - focusing high energy radiation at a focal position, said focal position being positionable within said optical waveguide, said radiation being generated in pulsed mode by a radiation source, and a focusing device for focusing said high energy radiation being movably supported; - moving a focal position inside the optical waveguide, 13. A method comprising: varying a rotational speed of the optical waveguide while moving a focal position within the optical waveguide. (10) 10. The method for introducing micro-modifications into an optical waveguide according to claim 9, characterized in that the focal position is moved continuously inside the optical waveguide. (11) A method for introducing micro-modifications into an optical waveguide according to (9) or (10), characterized in that the movement of the focal position inside the optical waveguide is a combination of rotational and translational motion. (12) The method for introducing micro-modifications into an optical waveguide according to (9), characterized in that the arrangement of the micro-modifications on the cut surface is comprised of one or more parameters selected from a group of parameters including a symmetrical arrangement of the micro-modifications, a density of the micro-modifications on the cut surface, a size of the micro-modifications, a distance of the micro-modifications relative to an optical waveguide axis extending in the longitudinal direction of the optical waveguide, a spacing between the micro-modifications, an orientation of the micro-modifications, or a group of other parameters used to describe the position and distribution of the micro-modifications, or the size or shape of the micro-modifications. (13) The method for introducing micro-modifications into an optical waveguide according to any one or more of (9) to (12), characterized in that the direction of incidence of the radiation into the optical waveguide is such that an optical waveguide axis extending in the longitudinal direction of the optical waveguide forms an angle not equal to 90° with the direction of incidence. (14) A method for introducing micro-modifications into an optical waveguide according to any one or more of (9) to (12), characterized in that the direction of incidence of the radiation into the optical waveguide is such that an optical waveguide axis extending in the longitudinal direction of the optical waveguide and the direction of incidence form an angle not equal to 90°±5°. (15) A method for introducing micro-modifications into an optical waveguide according to any one or more of (9) to (12), characterized in that the direction of incidence of the radiation into the optical waveguide is such that an optical waveguide axis extending in the longitudinal direction of the optical waveguide and the direction of incidence form an angle not equal to 90°±10°. (16) A method for introducing micro-modifications into an optical waveguide according to any one or more of (9) to (15), characterized in that the focusing device is additionally vibrated in the lateral and transverse directions. [Explanation of symbols]

[0074] 1 Optical waveguide 11 Optical waveguide core 12 Optical waveguide jacket 13 Optical Waveguide Coatings, Buffers and / or Other Layers 14 End Cap 15 Proximal end of optical waveguide 16 Distal end of optical waveguide 17 Optical waveguide axis 2 Laser beam 20. Apparatus for introducing micro-modifications into optical waveguides 21 Symbolically represented focusing optics 22 Focused laser beam 23 Polarizing Mirror 24 Condensing optics 25 Optical axis 31 Rotating device 32 Optical waveguide holder / guide 33 Lateral positioning device 34 Vertical positioning device α Rotation of the optical waveguide around the optical waveguide axis β1, β2, β3 Rotation of the laser beam incidence direction 40 How to introduce micro-modifications into optical waveguides 41 Process of attaching the optical waveguide to the holder 42. Focusing the laser radiation at a focal position 43 A process of moving the focal position in a predetermined pattern through an optical waveguide 44. Repeating the process of moving the focal position through the optical waveguide in a predetermined pattern. 5, 51, 52, 53, 54, 55, 56 Micromodification γ: the angle of the longitudinal orientation of the micromodification with respect to the optical waveguide axis A, B, C, D, E Radial cuts through the optical waveguide, which may be inclined F Axial cut through the optical waveguide A, B, C, D, E, F, G, H, J Regions of optical waveguide with arrayed micromodifications m is the number of repeats of a sequence that has multiple regions with different sequences of micromodifications n is the maximum number of repeats of a sequence that has multiple regions with different sequences of micromodifications

Claims

1. 1. A method for introducing micro-modifications into an optical waveguide, comprising the steps of: a step of fixing an optical waveguide to a holder, the optical waveguide and / or the holder being movably supported; focusing the high energy radiation at a focal position by a focusing device, the focal position being positionable within the optical waveguide, the high energy radiation being generated in a pulsed mode by a radiation source, the focusing device and the optical waveguide being configured to provide continuous linear movement between the optical waveguide and the focal position simply by continuously moving the optical waveguide; and a step of continuously moving only the optical waveguide to change a focal position within the optical waveguide and varying a rotation speed of the optical waveguide; The method includes:

2. The method of claim 1 , wherein the movement of the focal position within the optical waveguide is selected depending on a repetition rate.

3. The method of claim 1 , wherein the focal position is moved continuously within the optical waveguide.

4. The method of claim 1 , wherein the movement of the focal position within the optical waveguide is a combination of rotational and translational motion.

5. 3. The method of claim 2, wherein the positioning of the focal point within the optical waveguide is correlated with the repetition frequency such that an ordered array of micro-modifications is produced in the optical waveguide.

6. The method of claim 5, wherein the arrangement of the micro-modifications on the cut surface of the optical waveguide is determined by one or more parameters selected from a group of parameters including a symmetrical arrangement of the micro-modifications, a density of the micro-modifications on the cut surface, a size of the micro-modifications, a distance of the micro-modifications relative to an optical waveguide axis extending in the longitudinal direction of the optical waveguide, a spacing between the micro-modifications, an orientation of the micro-modifications, or any other parameter used to describe the position and distribution of the micro-modifications, or the size or shape of the micro-modifications.

7. The method of claim 1 , wherein the direction of incidence of the radiation on the optical waveguide is at an angle not equal to 90° with an axis of the optical waveguide.

8. 10. The method of claim 1, further comprising oscillating the light collector laterally and transversely.

9. 8. The method of claim 7, wherein the direction of incidence of the radiation on the optical waveguide forms an angle with an axis of the optical waveguide not equal to 90°±5°.

10. 8. The method of claim 7, wherein the direction of incidence of the radiation on the optical waveguide forms an angle with an axis of the optical waveguide not equal to 90°±10°.

11. The method of claim 1 , wherein the micro-modifications of the optical waveguide are arranged to have at least two different distances in the cross-section relative to the axis of the optical waveguide.

12. The method of claim 1 , wherein the micro-modifications of the optical waveguide are arranged in a spiral along the optical axis of the optical waveguide.

13. The method of claim 1 , wherein the micro-modification on a first cross-section of the optical waveguide is repeated on at least one other cross-section.

14. The method of claim 13 , wherein a cut plane in which the sequence of the micro-modifications of the first cut plane is repeated is rotated by an angle relative to the first cut plane.

15. focusing optics for focusing the laser pulses within the optical waveguide; at least one motorized adjustment device that continuously moves the optical waveguide to provide continuous linear motion between the optical waveguide and the focused laser pulses; a holder for the optical waveguide; a rotation device that rotates the optical waveguide, and continuously moving the optical waveguide using at least one adjustment device attached to the motor to continuously move the focal position of the laser pulse within the waveguide and vary the rotation speed of the optical waveguide using the rotation device. A device that introduces micro-modifications into optical waveguides.

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