Positioning of light coupling points

Abstract

This invention relates to a method and apparatus (200) for locating an optical coupling point (11), and a method for generating a microstructure (100) at the optical coupling point (11). The method for locating the optical coupling point (11) includes the steps of: a) providing an optical component (10) including the optical coupling point (11), the optical coupling point having an interaction region (15) located outside a volume surrounded by the optical component (10); b) generating light radiation in a production area (120), the production area (120) at least partially overlapping the interaction region (15) of the optical coupling point (11), light being applied to a medium (19) located in the production area (120), wherein... The medium (19) alters light to generate light radiation; c) at least a portion of the generated light radiation is captured in a capture region (130), which at least partially overlaps with the interaction region (15) of the optical coupling point (11), and the spatial resolution distribution of the captured portion of the generated light radiation is determined; and d) the position of the optical coupling point (11) is determined based on the determined spatial resolution distribution of the captured portion of the generated light radiation, through which the generated light radiation or at least a portion of the generated light radiation is captured. Therefore, the optical coupling point (11) can be precisely positioned with a relative positioning tolerance better than 1 μm. Thus, low coupling loss can be achieved through optical connection with the optical component (10), and the microstructure (100) can be precisely placed at the optical coupling point (11).

Description

Technical Field

[0001] This invention belongs to the field of optical connections of optical components using optical coupling points, and relates to methods and apparatus for locating optical coupling points, as well as methods for generating microstructures at the optical coupling points. Optical components can be, for example, micro-optical components, such as lasers, optical fibers, optical chips with passive or active waveguides, photodetectors, lens systems, or filters. Other types of optical components are also conceivable. This method and apparatus are particularly suitable for integrated optics and optical structure and connection technologies. However, many more applications are possible. Background Technology

[0002] Methods and apparatus for locating optical coupling points are known in the prior art. Depending on the type of optical component, the position and orientation of the optical coupling point can be captured, in particular, by using a combination of camera images and a confocal detection method of an imaging system, which may be part of a photolithography system. In this case, it may often be necessary for the optical component to be transparent to the light used for detecting the coupling point and / or to have contrast in refractive index, color, or reflection, which can be identified using imaging optics. However, this is not the case in many material systems. For example, in the field of integrated optics, the optical fibers, fiber arrays, or material systems used for integrating optical chips exhibit very low refractive index contrast, making it significantly more difficult to identify waveguides at optical coupling points. Furthermore, the optical chip or the individual layers of these chips may be opaque at the wavelength used for detecting the coupling point; this is particularly true when the waveguide to be detected is covered by metallization. In addition, many optical components lack optically verifiable supplementary structures, such as alignment marks, which can serve as a basis for determining the position and / or orientation of the optical coupling point.

[0003] As described by Katagiri, T. et al. in *Optical microscope observation method of a single-mode optical-fiber core for precise core axis alignment*, *Journal of Lightwave Technology*, 2(3), 1984, pp. 277-28*, particularly in the case of optical fibers, a recurring technical requirement is to identify their cores as accurately as possible, which is essential when two fibers are joined together using a so-called “splitter method.” Despite the low refractive index contrast of conventional optical fibers, it is possible to identify the interface between the fiber core and cladding by providing appropriate back-collimated floodlight exposure in an optical microscope when viewed from above, through slight shading. In this case, the fiber axis must be approximately located at the focal plane of the microscope. However, in many cases, back-collimated floodlight exposure is not feasible. In this regard, in optical modules, such as optical transmitters, the fiber and waveguide are typically fixed to an opaque substrate, making back-side illumination impossible. In other cases, fibers are combined to form fiber arrays, resulting in weak core shading being superimposed by other structures in the fiber array with higher optical contrast, thus making identification even more difficult.

[0004] US 2006 / 0067625 A1 discloses an apparatus and method for adjusting the optical connection between a waveguide and an optical connector, the optical connector introducing light into the waveguide or receiving light emitted from the waveguide. The apparatus includes an excitation source that emits light into the waveguide via the optical connector, the light causing the waveguide to fluoresce; an observation device that observes the waveguide from a side surface, different from an end surface, through which light is coupled into or emitted from the waveguide, and that receives the fluorescence emitted from the waveguide; and a connection adjustment device that adjusts the optical connection between the optical connector and the waveguide based on the intensity of the received fluorescence.

[0005] WO 2017 / 059960 A1 discloses another method for identifying the core of an optical fiber when viewing the facets from above, with the viewing direction perpendicular to the facets and parallel to the core's axis. To improve the visibility of the core at one end, light can also be coupled into the core from the other end of the fiber. However, the light coupled from the core must be collected by a system used for imaging. This proves difficult, especially if the optics of the lithography system are intended for imaging. The axis of the fiber or waveguide to be located is typically located at the focal plane of the lithography system, resulting in the inability to verify the axis-coupled light, even with the aid of objectives with high numerical apertures.

[0006] WO 2018 / 024 872 A1 discloses a method and apparatus for photolithographically generating a target structure on a non-planar initial structure by exposing a photoresist using at least one photolithography beam. The method includes the steps of: a) capturing the morphology of the surface of the non-planar initial structure; b) using at least one test parameter for the photolithography beam and determining the interaction between the photolithography beam and the initial structure, and the final changes of the photolithography beam and / or the target structure to be generated; c) determining at least one correction parameter for the photolithography beam such that the changes in the photolithography beam and / or the target structure to be generated caused by the interaction between the photolithography beam and the initial structure are reduced; and d) exposing the photoresist on the initial structure using at least one photolithography beam and at least one correction parameter for the photolithography beam to generate the desired target structure.

[0007] As described in Barry R. Masters, Review of Handbook of Biological confocal Microscopy, 3rd Edition, Journal of Biomedical Optics 13(2), 029902, 2008, imaging methods from the field of fluorescence microscopy can also be used to locate optical coupling points. For this purpose, fluorescence radiation in the sample under examination can be excited and / or verified in a spatially resolved manner, and the resulting contrast can be used for imaging.

[0008] According to Denk, Winfried, James H. Strickler, and Watt W. Webb, Two-photon laser scanning fluorescence microscopy, Science Vol. 248, No. 4951, 1990, pp. 73-76, spatially resolved excitation can also be achieved by using a multiphoton absorption process.

[0009] Purpose of the invention

[0010] Based on this disclosure, the object of the present invention includes providing a method and apparatus for locating optical coupling points, and a method for generating microstructures at optical coupling points, which at least partially overcome the aforementioned disadvantages and limitations of the prior art. The method and related apparatus are intended particularly for use in lithography systems that can be used to generate very precise structures aligned with or aligned to the optical coupling point, such as optical waveguides, lenses, mirrors, or other functional elements optically connected to or aligned with the coupling point to be detected. To obtain the lowest possible coupling loss during the optical connection between the optical coupling point to be located and the lithographically generated structure, it is desirable to locate the optical coupling point as precisely as possible in terms of position and orientation within the coordinate system of the lithography unit. For this purpose, a relative positioning tolerance preferably better than 1 μm, particularly preferably better than 200 nm, and particularly better than 50 nm is particularly desirable. Summary of the Invention

[0011] This objective is achieved by using a method and apparatus for locating optical coupling points, and by using a method for generating microstructures at the optical coupling points, the method having the features of the independent claim. Advantageous embodiments are given in the dependent claims, which can be implemented individually or in any desired combination.

[0012] In the following text, the terms “have,” “contain,” “include,” or “include,” or any grammatical variations thereof, are used in a non-exclusive manner. Thus, these terms can refer to a situation where no other features exist besides those introduced by these terms, or to a situation where one or more other features exist. For example, the expressions “A has B,” “A contains B,” “A includes B,” or “A includes B” can refer to a situation where no other elements exist in A besides B (i.e., A consists only of B), or to a situation where one or more other elements exist in A besides B, such as element C, elements C and D, or even other elements.

[0013] Furthermore, it should be noted that the terms "at least one" and "one or more," and their grammatical modifications, are typically used only once if they are used in conjunction with one or more elements or features and are intended to express the fact that the elements or features may be provided individually or multiple times, such as when the feature or element is first introduced. When the feature or element is subsequently mentioned again, the corresponding terms "at least one" or "one or more" are generally no longer used, without limiting the possibility that the feature or element may be provided individually or multiple times.

[0014] Furthermore, in the following text, the terms “preferredly,” “particularly,” “e.g.,” or similar terms are used in conjunction with optional features, while alternative embodiments are not limited in this respect. In this regard, the features introduced by these terms are optional features, and the scope of the claims, particularly the independent claims, is not limited by these features. In this respect, those skilled in the art will recognize that the invention can also be implemented using other configurations. Similarly, features introduced by “in one embodiment of the invention” or “in an exemplary embodiment of the invention” are understood as optional features and are not intended to limit the scope of alternative configurations or the independent claims. Furthermore, all possibilities of combining features introduced by introductory expressions with other features, whether optional or non-optional, are intended to be unaffected by these introductory expressions.

[0015] In a first aspect, the present invention relates to a method for locating an optical coupling point, the method comprising the following steps, preferably performed in an indicated order, beginning with step a) and ending with step d), wherein one or more, particularly directly consecutive, steps may also be performed at least partially simultaneously:

[0016] a) Provide an optical component including optical coupling points, wherein the optical coupling points have interaction regions located outside a volume surrounded by the optical component;

[0017] b) Generating light radiation in a production area, wherein the production area at least partially overlaps with the interaction area of ​​the light coupling point, wherein light irradiates a medium located in the production area, and the light is altered by the medium in a manner that generates light radiation.

[0018] c) Capturing at least a portion of the generated optical radiation in the capture region, wherein the capture region at least partially overlaps with the interaction region of the optical coupling point, and determining the spatially resolved distribution of the captured portion of the generated optical radiation; and

[0019] d) Determine the location of the optical coupling point based on the spatially resolved distribution of the captured portion of the generated light radiation.

[0020] At least a portion of the light radiation generated or captured through the optical coupling point.

[0021] Step a) involves providing an optical component. The term "optical component" refers to at least one optical element designed for emitting, receiving, altering, or transmitting light. An optical component may include, for example, an optical fiber, or may be applied to a planar or non-planar substrate, and is preferably manufactured using two-dimensional or three-dimensional microstructural methods. In cases where it is substantially planar, the optical component may also be referred to as an "optical chip," if appropriate. In this case, the optical component may comprise a single optical element or multiple optical elements. Preferably, the optical component is selected from the group comprising single-mode or multimode optical fibers made of organic or inorganic materials, semiconductor-based integrated optical chips (in particular lasers, optical amplifiers, photodiodes, superluminescent diodes, or silicon photonic chips), semiconductor- or dielectric-based integrated optical chips (preferably glass, silicon dioxide, silicon nitride, or polymers); optical circuit boards; or optical elements for free-space optics (in particular lenses, beam splitters, isolators, thin-film filters, mirrors, or diffraction gratings). Optical components may include optical waveguides with low refractive index contrast, such as glass-based waveguides, or waveguides with medium or high refractive index contrast, such as semiconductor-based waveguides. Other types of optical components are conceivable, particularly filters, power dividers, or electro-optic modulators. In principle, optical components may also include any desired combination of the aforementioned optical elements.

[0022] The optical component provided in step a) includes an optical coupling point. The term "optical coupling point" refers to a portion of the optical component to be connected, through which light can be coupled into or emitted from the component. In simple optical components, such as optical fibers or edge-emitting integrated optical chips, the optical coupling point is often also referred to as a "surface" or "waveguide surface." In the case of a photodiode, the optical coupling point is typically the same as the so-called "active region" of the pn junction used for verification, within which incident light causes the generation of an electrical signal. In the case of a laser, this region can be the edge or surface of the corresponding chip, representing the light-emitting area. More complex embodiments of the optical coupling point can be configured, for example, as a so-called grating coupler in silicon photonics (see Taillaert, Dirk, Peter Bienstman and Roel Baets, Compact efficient broadband grating coupler for silicon-on-insulator waveguides, Optics Lett. 29(23), 2004, pages 2749-51), or as a so-called “inverted cone” or etched micromirror (see Behfar, Alex et al., Horizontal cavity surface-emitting laser (HCSEL) devices, Vertical-Cavity Surface-Emitting Lasers IX. Vol. 5737, International Society for Optics and Photonics, 2005). The optical coupling point may already include, or may be provided with, beam-shaping elements generated by multiphoton aggregation.

[0023] Optical coupling points have interaction regions. In this context, the term "interaction region" refers to the spatial region that optically interacts with the coupling point. Selected points within this spatial region interact with the optical coupling point.

[0024] (1) If light emitted from the optical coupling point can at least partially reach a selected point in the spatial region, or

[0025] (2) If the light radiation is emitted by an isotropic radiation point source (the isotropic radiation point source is located at a selected point in the spatial region), then the light radiation can be coupled into the light coupling point at least partially.

[0026] In case (1), the selected point in the spatial region is located within the so-called "emission region" of the optical coupling point, and in case (2), the selected point is located within the so-called "receiving region" of the optical coupling point. The emission region of the coupling point can be described according to the conventional definition in the context of a so-called "Gaussian beam" as follows: if the intensity of the light emitted from the optical coupling point (measured at that point) is greater than 1 / e of the maximum intensity value measured at the same distance from the optical coupling point (e.g., on the axis of the Gaussian beam). 2 If the input coupling efficiency of the light emitted by the point source at that point is greater than 1 / e of the maximum input coupling efficiency obtained by the point source, then that point belongs to the radiation region of the optical coupling point. The receiving region can be defined similarly as follows: if the input coupling efficiency of the light emitted by the point source at that point is greater than 1 / e of the maximum input coupling efficiency obtained by the point source... 2 If the distance is equal to the distance from the optical coupling point, then the point belongs to the receiving region of the optical coupling point. The point light source is optimally located at the same distance from the optical coupling point, for example, on the axis of the Gaussian beam. Depending on the application, other coefficients, such as 0.01 (-20 dB) or 0.001 (-30 dB), can be used instead of the aforementioned coefficient 1 / e. 2 Therefore, the interaction region assigned to the selected optical coupling point in each case can also be referred to as a "receiving region" or a "emitting region". In a particularly preferred configuration of the invention, the interaction region is located outside the volume surrounded by the optical components. However, in alternative configurations, the interaction region may also comprise, in whole or in part, the volume of the optical components or the waveguide core formed by the optical components. In the case where the exemplary optical components comprise a simple waveguide with optical coupling points arranged at the ends of the waveguide, the interaction region may have a tapered volume, also referred to as a "receiving cone" or "emitting cone".

[0027] Step b) involves generating optical radiation in a spatial region referred to as the “production region.” The terms “generation” and “production” in relation to optical radiation refer to the provision of optical radiation, specifically by radiating light into the production region, where the light can be altered to produce optical radiation. In this case, radiation can be generated using various effects based on, for example, light scattering, phosphorescence, fluorescence, luminescence, or related processes. In cases based on light absorption and downstream emission, simultaneous or sequential absorption of multiple photons can also be used. In this case, the optical radiation used for excitation can be provided by the optical coupling point itself or by a separate optical system configurable for generating a laser beam.

[0028] The term "light" refers to photons provided by a light source that generate desired light radiation in the production area. The light radiated into the production area to generate light radiation can be provided as a light wave with constant power or in the form of short light pulses; that is, the light source can be configured as a continuous wave source or a pulsed source. In the case of a pulsed source, light pulses with a pulse duration preferably at most 10 ps, ​​more preferably at most 1 ps, particularly preferably at most 200 fs, particularly at most 100 fs, and a repetition frequency preferably at least 1 MHz, more preferably 10 MHz, particularly preferably at least 25 MHz, particularly at least 100 MHz can be used. Laser sources, particularly suitable for this purpose, are selected from fiber-based femtosecond lasers or pulsed solid-state lasers, such as Ti:sapphire lasers or diode lasers, which can be combined with frequency conversion devices, for example, for frequency doubling, for summation frequency generation, or for differential frequency generation. In this preferred configuration, the light source can be specifically used to excite the emission of a multiphoton absorption process. For example, in this case, a multi-stage absorption process can also be used to excite luminescence, wherein a portion of the excitation light or de-excitation light can be radiated into the production area through optical components, and another portion can be radiated into the production area through an objective lens.

[0029] The light radiation generated according to step b) can, in principle, include any type of light radiation having a wavelength within or adjacent to the spectral range. While the visible spectrum has wavelengths from 380 nm to 780 nm, the infrared spectral range includes wavelengths from 780 nm to 1 nm, particularly from 780 nm to 3 μm (near-infrared "NIR") or from 3 μm to 8 μm (mid-infrared "MIR"), while the ultraviolet spectral range includes wavelengths from 1 nm to 400 nm, preferably from 100 nm to 400 nm, particularly from 400 nm to 315 nm ("UV-A"), 315 nm to 280 nm ("UV-B"), or 280 nm to 100 nm ("UV-C").

[0030] According to step b), the production area at least partially overlaps with the interaction area of ​​the optical coupling point. In this case, the two areas may have a smaller overlap area than each of the two areas; or the two areas may be identical, or one of the areas may be completely surrounded by the corresponding other area.

[0031] Step c) involves capturing at least a portion of the generated optical radiation in the capture region and also determining the spatially resolved distribution of the captured portion of the generated optical radiation, wherein the capture region at least partially overlaps with the interaction region of the coupling point. Here, the two regions may also have a smaller overlap than each of the two regions; or the two regions may be identical, or one region may be completely surrounded by the corresponding other region.

[0032] The terms "capture" and "seize" in relation to generated optical radiation refer to a metrological record of the optical radiation or a portion thereof, particularly a metrological record of its power, wherein the captured radiation may be further modified, particularly with regard to wavelength or polarization filtering, before the power is determined. In one case, where an optical coupling point is used to capture the generated optical radiation, the extent to which the optical radiation can couple into the optical coupling point from a corresponding production location in the production area can be metrologically recorded. In another case, where a separate optical system is used to capture the generated optical radiation, the optical system can, in particular, metrologically record the power of the optical radiation or a portion thereof at a corresponding production location in the production area. In both cases, it is sufficient to capture a portion of the generated optical radiation in the overlapping area between the production area and the capture area, while another portion of the optical radiation can be emitted in a spatial direction that cannot be captured by the measuring device configured to capture the optical radiation.

[0033] Regarding spatially resolved distribution, the terms "determine" and "resolve" refer to determining the spatially resolved distribution of the optical radiation produced by the portion captured within the capture region, particularly by verifying and evaluating recorded measurements and / or by applying a model for the optical coupling point or the interaction region of the optical coupling point. The term "spatially resolved distribution" in relation to optical radiation refers to a variable specified as a function of spatial location within the spatial region, preferably in the form of a position vector in a three-dimensional coordinate system. The variable used in this context could be, particularly, location-related, the power of the captured optical radiation or the input coupling efficiency of the optical power produced by the optical system at the corresponding spatial location.

[0034] Step d) involves desirably determining the location of the optical coupling point from a spatially resolved distribution (determined in step c), the spatially resolved distribution being the spatially resolved distribution of the light radiation generated by the portion captured within the capture region. The term "location" includes an indication of spatial position and an indication of the direction of the optical coupling point or the direction of the interaction region of the optical coupling point. In this case, the indication of spatial position may particularly include a position vector in a coordinate system, preferably a three-dimensional coordinate system. The indication of direction may particularly include one or more three-dimensional orientation vectors, particularly preferably in the same coordinate system also used to indicate the position vector, one of which preferably indicates the direction from which light can be emitted from the optical coupling point, or from which effective input coupling of light into the optical coupling point is possible. As explained in more detail below, in a particularly preferred configuration, the position vector and orientation vector can be represented in a three-dimensional coordinate system defined by the lithography system used in the lithography method. In the case of diverging beams, the optical axis of the beam emitted from or received by the optical coupling point can be used to describe the direction of the optical coupling point or the direction of the interaction region of the optical coupling point. In addition, at least one additional orientation vector may be indicated, in particular an orientation vector that defines the direction of rotation of the coupling point relative to the optical axis, and thus specifically indicates the spatial direction of polarization of light emitted from or captured by the coupling point.

[0035] Regarding the location of the optical coupling point, the term "determined" or "identified" means determining a variable from other variables, which are captured quantitatively or determined according to a model. Therefore, the position and orientation of the optical coupling point can be determined from a spatially resolved distribution (determined in step c), which is the spatially resolved distribution of the light radiation generated by the portion captured within the capture region. In addition to the position and orientation of the optical coupling point, information about the lateral shape of the interaction region and / or other position-related characteristics of the interaction, such as polarization dependence, can also be obtained. The position and orientation of the optical coupling point or the interaction region of the optical coupling point can generally be derived directly from the spatially resolved distribution of the power captured in the capture region (determined according to step c). In this case, the position of the coupling point can typically constitute the position of a very small lateral extent of the interaction region, such as the apex of a conical spatial region. Alternatively or additionally, observations or model-based expectations that the light radiation is not significantly excited within the optical component, particularly within the waveguide included by the optical component, can influence the determination of the position and orientation of the optical coupling point. As a result, the appearance or disappearance of captured light radiation typically occurs at the coupling point, particularly in the form of abrupt contrast changes, which can be used to determine the position of the optical coupling point. If the optical radiation is locally excited by a separate optical system including an objective lens, it is particularly advantageous to detect a portion of the radiation that is generated globally in the medium but is not coupled into the optical component through the optical coupling point and is trapped within the optical component, in addition to detecting the radiation coupled into the optical component through the optical coupling point. In this case, detection can be achieved by using the objective lens used for excitation or by using an additional objective lens. Furthermore, the expected interaction region for the optical coupling point is usually calculable or modelable, particularly by applying Kirchhoff's diffraction integrals. In this case, the location of the optical coupling point and its interaction region can be derived by comparing the model-based interaction region or model-based distribution of the trapped optical power with the optical power metrically determined within the trapped region. Therefore, it is possible to determine the location and orientation of the optical coupling point without actually metrically capturing that portion of the spatial region including the optical coupling point. The location and orientation of the optical coupling point can then be determined, for example, by extrapolation of the distribution of captured radiation in the interaction region. In this respect, for example, in the case of a conical interaction region, it is sufficient to capture only the widened region of the cone, while the location of the cone's apex is determined by extrapolation.

[0036] In one particular configuration, the location of the optical coupling point can be determined by the wavelength of the generated radiation and / or the wavelength of the light used to generate the radiation, which differs from the operating wavelength of the optical components. In this configuration, color effects may occur, such as wavelength-dependent refraction of light radiation at the interface, which can be compensated for using a model. In another configuration, the location and orientation of the optical coupling point are sufficiently insensitive to wavelength, thus eliminating the need for compensation for color effects.

[0037] According to the present invention, the manner in which light radiation is generated in the production area is not important, as long as the spatially resolved distribution of the light radiation generated or captured is satisfactory, i.e., preferably...

[0038] (1) It produces light radiation, or

[0039] (2) Optionally captures the spatially resolved distribution of light radiation.

[0040] This is achieved through the optical coupling point. In case (2), the spatially resolved distribution of the light radiation captured through the coupling point can be determined, for example, by the light radiation generated at various points inside or outside the interaction region in a known spatial distribution order, and the light power quantitatively captured through the coupling point reflects the positional dependence of the input coupling efficiency, thereby reflecting the shape of the interaction region. In this case, the term "through the optical coupling point" refers to the configuration according to the invention regarding the guidance of the light radiation or the light that generates the light radiation, such that the light radiation or the light that generates the light radiation actually passes through the optical coupling point. Only in this way can it be ensured that the spatially resolved distribution of the captured light radiation actually indicates the location of the optical coupling point or the associated interaction region.

[0041] To generate light radiation in the production area, the production area includes at least a medium that modifies the incident light in a manner that generates light radiation. For this purpose, the production area can be wholly or partially filled with a medium, the term "medium" referring to a substance configured to generate light radiation from light radiating into the production area. Therefore, providing a medium in the production area particularly enables the resolution of the problem that light emitted from optical components typically cannot be effectively coupled into the objective lens, or conversely, that light radiating into the spatial region through the objective lens typically cannot be effectively radiated into the optical components. In this case, advantageously, the medium can wholly or at least partially fill the overlapping area between the production area and the capture area. In a particularly preferred configuration, portions of the production area or capture area can be addressed sequentially in each case. This can be achieved, for example, using a scanning method capable of changing the relative position of the objective lens with respect to the optical components. Alternatively, a fixed objective lens can also be used, and scanning can be achieved by means of a scanning mirror, which can be used to address specific portions of the production area or capture area. Alternatively or additionally, detector arrays or image sensors, such as CCD or CMOS arrays, can be used in combination with fixed objectives for spatially resolved capture of radiation.

[0042] In a preferred configuration, the medium located in the production region may include a scattering center that scatters incident light to generate scattered radiation, which, as desired light radiation, can completely or at least partially fill the capture region. In an alternative, equally preferred configuration, the medium located in the production region may include a luminescent dye, in which case the luminescent dye generates luminescent radiation when light is irradiated thereon, which, as desired light radiation, can also completely or at least partially fill the production region. In this case, luminescence can be excited using a single-photon or multi-photon absorption process. In this context, the term "luminescence" describes light emitted by a substance configured to enter an excited state by absorbing energy, returning to the ground state through the emission of radiation. If the emission of radiation occurs directly after light absorption, the term "fluorescence" is generally used, while the term "phosphorescence" is used for a longer period before returning to the ground state. However, other types of luminescence are also conceivable. Optionally, the starting material configured to generate the luminescent dye may also be located in the production region, in which case the starting material first generates the luminescent dye when incident light is irradiated thereon, and then generates the desired luminescent radiation upon further irradiation of light, which appears as light radiation in the production region. Other types of media can be considered.

[0043] In a particular configuration, the optical component may comprise, in whole or in part, a medium that alters the incident light to generate optical radiation. In this case, the medium may preferably exist within the optical component in the form of a waveguide core, into which a scattering or luminescent material is introduced. Optionally or additionally, the inherent fluorescence of the waveguide material may be used for this purpose.

[0044] In another configuration, the medium may include a photoresist, in which case the dose of photoresist introduced to generate light radiation is preferably below the dose threshold of the photoresist polymerization. The term "photoresist" may also be replaced by "photoresist" in German. In this case, the photoresist may include a scattering center or a luminescent dye. Preferably, the excitation wavelength, power, pulse shape, or irradiation duration of the luminescent dye used to generate light radiation can be selected such that unintentional exposure of the photoresist does not occur. After the optical coupling point is located according to the method described herein, the microstructure can be generated according to a method for generating microstructures at such located optical coupling points (explained in more detail below).

[0045] In a preferred embodiment of the invention, light can be emitted by an optical component through an optical coupling point, such that the light propagates into the interaction region or the emission region of the optical coupling point, and therein generates desired light radiation, which is captured and evaluated in a spatially resolved manner by an objective lens. Since it is generally not possible to directly capture light emitted by the optical component, even with a high numerical aperture (NA), particularly by introducing scattering centers or luminescent dyes into the interaction region, it is possible to capture the desired light radiation throughout the entire interaction region or at least a portion thereof. Therefore, spatially resolved detection of the light radiation captured by the objective lens makes it possible to directly measure at least a portion of the interaction region of the optical coupling point. Spatial-resolved detection of the light radiation can be achieved using known microscopy methods, preferably using a camera or confocal microscope.

[0046] In another preferred configuration of the invention, light can be emitted by a separate optical system including an objective lens, such that the light propagates into the receiving region of the interaction region or the optical coupling point, and there generates the desired light radiation, which is captured and evaluated by the optical component through the optical coupling point. Since light emitted by the objective lens is generally not directly coupled into the optical component even if the objective lens has a high numerical aperture (NA), in particular, the aforementioned introduction of scattering centers or luminescent dyes into the interaction region of the optical coupling point makes it possible to generate the desired light radiation throughout the interaction region or at least a portion thereof and couple it into the optical coupling point. The capture of the light radiation coupled into the optical component (preferably having a waveguide) can preferably be achieved directly at the output of the optical component. For this purpose, a measuring device can preferably be installed at the output of the optical component, particularly preferably a power detector (especially in the form of an optical power measuring head), which can also be equipped with a filter, for example, for capturing a specific wavelength or polarization state. This configuration is particularly advantageous for optical fibers, such as single-core or multi-core fibers. However, a power detector can also be provided as part of an optical component, for example, in the case of an integrated photodiode, which can be configured to capture at least a portion of the power of one or more waveguides. Furthermore, the coupled-in light radiation can also be captured by an objective lens used for excitation, in which case, as described below, the output coupling point on the optical component itself can be used. Alternatively, an additional objective lens can also be used to capture the light radiation. Typically, to quantitatively capture the light radiation, a lock-in principle can be used to distinguish between background radiation (e.g., external illumination) and the light radiation generated for detecting the coupling point.

[0047] In one particular configuration, the output coupling structure at the optical components (especially in the waveguide formed by the optical components) is located within the objective's addressable field of view. This structure can be used to re-emit a portion of the optical power coupled into the optical components in the direction of the objective, allowing this portion to be captured by the objective. For this purpose, scattered radiation emitted by the waveguide can also be used, particularly due to defects in the waveguide (e.g., surface roughness), or through a scattering structure created for this purpose. In this particular configuration, the optical radiation generated in the interaction region at the coupling point can have a wavelength different from the waveguide's operating wavelength, resulting in the capture of the scattered radiation not necessarily accompanied by a loss of the operating wavelength itself. The scattered radiation is generated by the waveguide through an emitting element. For example, a portion of the waveguide made of a so-called "subwavelength grating" (SWG) can be used, resulting in the emission of optical radiation generated in the receiving volume while these radiations do not affect or significantly affect the optical signal at the operating wavelength of the optical components. Furthermore, a portion of the waveguide can be provided with additional dye, which can be excited by the coupled-in optical radiation; in this case, the emitted light coupled out of the waveguide can also be captured by the objective.

[0048] In another embodiment, the optical component may have a set of optical coupling points, in which case it is advantageous to capture the light radiation coupled into the entire set as a whole, especially if the interaction regions allocated to each optical coupling point have sufficiently large spatial regions that do not overlap with each other. An example of this is a multi-core optical fiber having a common photodetector mounted at the end of the multi-core fiber, the effective area of ​​which extends over all the cores of the multi-core fiber.

[0049] In another aspect, the present invention relates to a device for locating optical coupling points, wherein the device comprises:

[0050] - An optical component, comprising at least one optical coupling point, wherein the optical coupling point has an interaction region located outside a volume surrounded by the optical component;

[0051] - An optical device configured to generate light radiation in a production region and / or to capture at least a portion of the generated light radiation in a capture region, wherein the production region and the capture region at least partially overlap with the interaction region of the optical coupling point; and

[0052] - An evaluation device configured to determine the spatially resolved distribution of the captured portion of the light radiation, and to determine the location of the optical coupling point based on the determined spatially resolved distribution of the captured portion of the light radiation.

[0053] The device is configured to generate or capture at least a portion of the generated light radiation through an optical coupling point.

[0054] The term "optical device" refers to an apparatus configured to generate and capture light radiation, comprising optical components configured for this purpose, particularly a light source configured to allow light to irradiate a medium located in a production area, the light source radiating light into the production area via an optical coupling point or via an optical system, a measuring device (particularly a measuring device in the form of a power detector), configured to capture at least a portion of the generated light radiation in a capture area, and may consist of optical components or an optical system, or may include components of optical components and components of an optical system, and may include an optical system configured to transmit and optionally modify the generated and / or captured light radiation.

[0055] Preferably, in this case, the light source can be configured as a pulsed light source for generating light pulses having a pulse duration of at most 10 ps, ​​preferably at most 1 ps, particularly preferably at most 200 fs, and especially at most 100 fs; and a repetition rate of at least 1 MHz, preferably at least 10 MHz, particularly preferably at least 25 MHz, and especially at least 100 MHz. Laser sources, such as fiber-based femtosecond lasers or pulsed solid-state lasers, such as Ti:sapphire lasers, are particularly suitable for this purpose. Alternatively, a continuous-wave light source can also be used.

[0056] As described above, the light source is preferably configured to radiate light into at least a spatial region comprising a medium for generating light radiation by altering the incident light. The spatial region generating light radiation by altering the incident light due to the medium is also referred to hereinafter as a production region. The production region at least partially overlaps with the interaction region of the optical coupling point. In this case, the two regions may have a smaller overlap than each of the two regions; or the two regions may be identical, or one region may be completely surrounded by the corresponding other region. Further details regarding the medium and its advantageous configuration are provided in the remainder of the specification. Preferably, in this case, the refractive index of the medium may be matched to the refractive index of the objective lens configured for radiating light or for capturing the generated light radiation, particularly to improve the resolution of the objective lens.

[0057] As previously stated, the term "optical system" refers to an apparatus composed of optical devices configured to transmit and optionally modify generated and / or captured light radiation, and for this purpose includes at least one optical element, preferably at least one optical lens, capable of generating or capturing light radiation in a spatially resolved manner. For a given vacuum operating wavelength λ of the optical component, the spatial resolution of the production or capture process is preferably 0.01λ to 100λ, particularly preferably 0.05λ to 10λ, especially 0.1λ to 10λ. In a particularly preferred configuration, the optical system configured to generate or capture light radiation in a spatial region includes at least one objective lens. Preferably, lithography objectives with a high numerical aperture (NA) are suitable for achieving high spatial resolution. In this case, the term "high numerical aperture" preferably means that the numerical aperture of the objective lens is greater than 0.3, particularly preferably greater than 0.6, especially greater than 0.8, or even greater than 1.0. In particular, during the application of the method for generating microstructures at optical coupling points, as described in more detail below, preferably using three-dimensional direct-write laser lithography, the same objective lens also used for generating microstructures can be used to capture or generate light radiation. Besides the reduction in the number of components, this also has the advantage that potential imaging aberrations of the objective lens, such as field distortion, are irrelevant or at least partially compensated for. In one particular configuration, the objective lens can, in this case, be in direct contact with a photoresist used as an immersion medium. The photoresist can also be used simultaneously as a medium to alter incident light and generate optical radiation in an associated manner. In this case, in a preferred embodiment, the photoresist can be mixed with a substance that, by means of incident light, allows optical radiation to be generated through light scattering, phosphorescence, fluorescence, luminescence, or related processes.

[0058] To determine the spatially resolved distribution of the captured light radiation, preferably, the position of the spatial element can be moved through a production area or a capture area, in which light radiation is generated by a change in the incident light or by the captured radiation, and in this process, the dependence of the power of the captured radiation on the position of the spatial element can be determined. For this purpose, preferably, a beam scanner can be used, which allows rapid deflection (particularly perpendicular to the beam direction) of the incident or captured beam through the production or capture area. The beam scanner can preferably be selected from so-called "galvanometer scanners" and microelectromechanical systems (MEMS) based mirror scanners. Movement of the incident or captured beam along the beam direction can be achieved by means of movement of the objective lens and / or optical components. Alternatively, other devices can also be employed, particularly 3D scanners based on spatial light modulators or deformable mirrors. Further configurations are conceivable, particularly based on methods from confocal microscopy or laser scanning microscopy (LSM). In this case, the beam scanner can also be used for photolithography to produce microstructures.

[0059] In a particularly preferred configuration, the measuring device for determining the spatially resolved distribution of the captured optical radiation within the capture region may include a power detector configured to determine the optical power of the optical radiation. As mentioned above, the power detector may be provided, particularly, in the form of an optical power measuring head. Preferably, filters and / or beam splitters may be used to select the captured optical radiation. In particular, in this case, the filter may include a spectral filter configured to separate scattered radiation and emitted radiation. The filter used may also be used to capture a selected wavelength or polarization state. To determine the power of the optical radiation, it is particularly advantageous to use a low-noise power detector with high sensitivity for detecting small optical powers, especially a pin diode with a low-noise electronic amplifier or photomultiplier tube. Optionally or additionally, the power detector may be formed as part of an optical component, for example, in the case of an integrated photodiode. The measuring device may be configured as an integral part of an optical component or an optical system, or as a component of an optical component or an optical system. In particular, a photodiode implemented as part of an optical system may be used to detect optical radiation, and the capture, amplification, and evaluation of the electrical signal generated in the process may be achieved by functional devices of a corresponding configuration of the optical system. In another equally preferred embodiment, the coupled-in light radiation can be captured by an objective lens used for excitation, in which case, as described above, the output coupling point of the optical component itself can be used. Alternatively, an additional objective lens can be used to capture the light radiation. To verify the radiation, in all embodiments, a lock-in measurement principle is used so that it is possible to distinguish between background radiation (e.g., external illumination) and light radiation generated in the production area.

[0060] An evaluation apparatus configured to determine the location of an optical coupling point based on the spatially resolved distribution of the captured light radiation is preferably an electronically controllable device, particularly having a computer, microcomputer, or programmable chip, such as an application-specific integrated circuit (ASIC) or an FPGA (Field-Programmable Gate Array), wherein the device has access to a computer program configured to execute at least one of the methods of the present invention. To accurately locate the interaction region of the optical coupling point, the evaluation apparatus can be configured to deconvolve the spatial distribution of the excitation or capture of the light radiation (predefined by the objective lens). This is particularly advantageous if the excitation or capture is spatially distributed in at least one spatial direction, and the spatial distribution has the same or larger dimensions as the cross-section of the production or capture region at the relevant point.

[0061] For further details regarding the means for locating the optical coupling point, and in particular regarding the optical components and the associated at least one optical coupling point, please refer to the remainder of this document.

[0062] On the other hand, the present invention relates to a method for fabricating microstructures at optical coupling points. In this case, the method includes the following steps, which are preferably performed in an indicated order, starting with step i), followed by step ii), and additional steps are also conceivable:

[0063] i) Locate the optical coupling point according to the method for locating the optical coupling point described herein; and

[0064] ii) Microstructures are generated at the optical coupling point by using a manufacturing method selected from additive or subtractive manufacturing methods.

[0065] After locating the optical coupling point, the information determined regarding its position and orientation can be used to generate a microstructure at the optical coupling point, particularly by deriving the position and orientation of the microstructure from the information regarding the location of the optical coupling point. In a preferred embodiment, the microstructure can be an optical element directly adjacent to the optical coupling point, preferably an optical waveguide or some other micro-optical element. Optionally, the microstructure or a component thereof can be spaced apart from the optical coupling point. A preferred configuration may include the fabrication of a microlens, micromirror, or any desired combination of microlenses, micromirrors, and other micro-optical elements (especially optical waveguides). The microstructure or a component thereof can be aligned very precisely with the associated coupling point and configured, particularly in terms of shape, position, and orientation, to enable light with a specific amplitude and phase distribution to be effectively coupled into the optical coupling point through the microstructure. Conversely, light coupled from the coupling point can be converted into a predetermined amplitude and phase distribution through the microstructure or a component thereof. Such a configuration can be particularly used for optically connecting two optical components, wherein the amplitude and / or phase distribution emitted by the first optical component can be altered to enable effective input coupling to the other optical component.

[0066] In this context, the term "additive manufacturing method" refers to a production method that attaches or applies material to an initial structure, while the term "subtractive manufacturing method" refers to an alternative production method that removes material from the initial structure. In a preferred embodiment, material application or removal can be achieved by photolithography using a suitable photoresist (particularly a negative or positive resist). Therefore, the optical system described above for generating or capturing light radiation in the interaction region or a portion thereof can also be used to photolithographically generate microstructures at the optical coupling point. As mentioned above, the optical system can preferably include an objective lens with a high numerical aperture and high optical resolution. In a particularly preferred embodiment, the objective lens is also configured to generate three-dimensional microstructures using three-dimensional direct-write lithography. In this context, the term "three-dimensional direct-write lithography" refers to a microstructure method that makes it possible to structure or deposit one or more materials in an additive or subtractive manner in the form of a three-dimensional pattern or layout. Thus, three-dimensional structures with an accuracy preferably better than 1000 nm, particularly preferably better than 500 nm, and very particularly preferably better than 300 nm can be produced, wherein the term "three-dimensional" indicates the possible shape of the structure in one, two, or three spatial directions. In this context, the resolution of the three-dimensional direct-write lithography method can preferably be better than 10 μm, particularly preferably better than 5 μm, very particularly preferably better than 2 μm, or better than 1 μm or 500 nm, wherein the term "resolution" refers to the maximum range of the smallest structural elements that can be produced by this method. The three-dimensional direct-write lithography method can preferably be designed so that it can be performed under standard atmospheric conditions and does not require a vacuum. Additive or subtractive three-dimensional direct-write lithography is particularly suitable, allowing resolutions preferably greater than 50 μm. 3 / s, more preferably greater than 500 μm 3 / s, with a preferred size greater than 1000μm 3 / s, with a very high preference for sizes greater than 10000μm 3Material is deposited or removed at a rate of / s. In a particularly preferred configuration, three-dimensional direct-write lithography can be based on the principle of multiphoton lithography. In a particular configuration, the medium that generates the light radiation to be captured can be provided in the form of an immersion medium that is in direct contact with the coupling point to be located. In this case, the objective lens may or may not be in contact with the immersion medium itself. In this case, the immersion medium itself can be used as a photoresist to produce the desired microstructure, or it can be separated from the photoresist by a transparent film. In a preferred embodiment, by using incident light, a substance that generates light radiation by means of light scattering, phosphorescence, fluorescence, or luminescence can be introduced into the medium. In the case of photoresist, the fluorescence properties of the added components of the photoresist (especially the fluorescence properties of the photoinitiator) can be utilized, or a fluorescent dye can be added separately. In this case, the excitation of luminescence or fluorescence can be based on a single-photon process or a multiphoton process.

[0067] For further details regarding the method for generating microstructures at optical coupling points, refer to the description of the method and apparatus for locating optical coupling points according to the present invention.

[0068] Advantages of the invention

[0069] Compared with existing methods and optical systems, the present invention offers a number of advantages. The method and apparatus of the present invention for locating optical coupling points and optionally generating microstructures are particularly capable of achieving precise positioning of at least one optical coupling point, with relative positioning tolerances better than 1 μm, particularly preferably better than 200 nm, and especially better than 50 nm. The term "positioning tolerance" refers to the sum of all statistical and systematic deviations from the position determined metrically from the optical coupling point compared to its actual position.

[0070] Specifically, by using an interaction process, the direction of light propagation can be altered in such a way that the light radiated into the production area from the optical coupling point to be located or the lithography objective can be captured and located by the objective or the coupling point. In this case, the effective change of the direction of propagation can preferably be achieved by using a scattering center or by using a luminescent dye. A particularly preferred configuration includes a lithography system utilizing multiphoton fluorescence, preferably a photoinitiator. Since in each case, luminescence is excited only at the focal point of the lithography system, spatially resolved capture of the interaction region in three spatial directions at high resolution is possible. Attached Figure Description

[0071] Further details and features of the invention will become apparent from the following description of preferred exemplary embodiments, particularly in conjunction with the dependent claims. In this context, corresponding features may be implemented by themselves or as a plurality of features combined with each other. The invention is not limited to exemplary embodiments.

[0072] Exemplary embodiments are schematically illustrated in the following figures. In this context, the same reference numerals in the figures denote the same or functionally identical elements or elements that correspond to each other in terms of function.

[0073] Specifically, as shown in the attached diagram:

[0074] Figure 1 shows a schematic diagram of a particularly preferred exemplary embodiment of the method for locating optical coupling points;

[0075] Figure 2 shows a schematic diagram of the location, orientation, and associated interaction region of the optical coupling point;

[0076] Figure 3 shows a schematic diagram of another exemplary embodiment, in which the location of the optical coupling point is captured by exciting or capturing the luminescent radiation;

[0077] Figure 4 shows a schematic diagram of another exemplary embodiment, in which the localization of the optical coupling point is achieved by exciting or capturing scattered radiation;

[0078] Figure 5 shows a schematic diagram of another exemplary embodiment, in which the optical coupling points are arranged at a distance from the surface of the optical component;

[0079] Figure 6 shows a schematic diagram of another exemplary embodiment, in which the localization of the optical coupling point is captured by exciting luminescent radiation or scattered radiation in the waveguide core;

[0080] Figure 7 illustrates an exemplary embodiment of a microstructure generated at the optical coupling point in the form of a dielectric free waveguide;

[0081] Figure 8 illustrates an exemplary embodiment of a microstructure generated at the optical coupling point in the form of a microlens;

[0082] Figure 9 illustrates another exemplary embodiment, which includes multiple optical coupling points;

[0083] Figure 10 illustrates a preferred embodiment for capturing light radiation introduced at the optical coupling point or for coupling light to excite light radiation in the interaction region of the optical coupling point;

[0084] Figure 11 illustrates, by way of example, the interaction region of the coupling point of a surface-illuminated photodiode; and

[0085] Figure 12 shows a preferred exemplary embodiment of the device for locating optical coupling points according to the present invention. Detailed Implementation

[0086] Figures 1A and 1B respectively illustrate schematic diagrams of two particularly preferred exemplary embodiments of the method for locating optical coupling points 11 composed of optical components 10. The coupling point 11 has an associated interaction region 15. Preferably, the optical components 10 are selected from the group consisting of: single-mode or multimode optical fibers made of organic or inorganic materials; semiconductor-based integrated optical chips (especially lasers, optical amplifiers, photodiodes, superluminescent diodes, or silicon photonic chips); integrated optical chips based on semiconductor or dielectric materials (preferably glass, silicon dioxide, silicon nitride, or polymers); optical circuit boards; or optical elements for free-space optics (especially lenses, beam splitters, isolators, thin-film filters, mirrors, or diffraction gratings). The optical components may include optical waveguides with low refractive index contrast, such as glass-based waveguides, or waveguides with medium or high refractive index contrast, such as semiconductor-based waveguides. Other types of optical components 10 are conceivable, particularly filters, power dividers, or electro-optic modulators.

[0087] According to this method, optical radiation is specifically generated at least in the production region 120, which overlaps at least regionally with the interaction region 15. The generated optical radiation is captured in the capture region 130, which also overlaps at least regionally with the interaction region 15. Therefore, the optical radiation generated at a selected point 16 in the overlapping region between the interaction region 15 and the production region 120 interacts with the optical coupling point 11 because:

[0088] (1) Light emitted from optical coupling point 11 can reach selected point 16, or

[0089] (2) The light radiation emitted by the isotropic radiation point source located at the selected point 16 can be coupled into the light coupling point 11.

[0090] In the first case (1), the selected point of the spatial region 15 is located within the so-called “emission region” of the optical coupling point 11; and in the second case, it is located within the so-called “receiving region” of the optical coupling point 11.

[0091] For this purpose, in the embodiments according to Figures 1A and 1B, a medium 19 is used in each case, which at least partially fills the overlapping region between the production region 120 and the capture region 130. In this case, the medium 19 may particularly preferably comprise a material configured to generate optical radiation from light radiated into the production region 120. The light radiated into the production region 120 is preferably used to generate the desired optical radiation by using the medium 19 in a portion of the capture region 130, which may in particular be scattered radiation or luminous radiation. As schematically shown, in this case, the medium 19 may fill, wholly or partially, the overlapping region between the production region 120, the capture region 130, and the interaction region 15 of the optical coupling point 11 to be located.

[0092] In the embodiment according to FIG1A, the light used to generate optical radiation is provided by a light source 112 and emitted through an optical coupling point 11 into an interaction region 15 of the coupling point using an optical component 10. In this case, the interaction region 15 of the optical coupling point 11 and the production region 120 are preferably aligned at least near the coupling point. At a greater distance from the optical coupling point 11, it may occur that at points belonging to the interaction region 15, optical radiation cannot be generated by the light emitted from the optical coupling point 11 due to excessive absorption or scattering of light between the optical coupling point 11 and the relevant point. The light source 112 may preferably be a pulsed light source configured to generate light pulses. Alternatively, a continuous wave light source may also be used. In the embodiment shown in FIG1A, the spatially resolved distribution of the captured optical radiation in the capture region 130 is determined by using an optical system 111. For this purpose, an objective lens (preferably a photolithography objective lens) may preferably be used, which in each case achieves capture in the focusing cone 60 or only at the focusing point 61 or in a finite volume element surrounding the focusing point 61 within the capture region 130. During the capture process, for example in the form of a one-dimensional, two-dimensional, or three-dimensional scanning process, the position of the focusing cone 60, the focal point 61, or the associated volumetric element can preferably be changed by using a beam scanner included in the optical system 111. The light radiation captured by using the optical system 111 is transmitted to a measuring device 110 for evaluation, which can be implemented, in particular, in the form of a power detector. Additionally or alternatively, the measuring device 110 may include a camera sensor or an array of one-dimensional or multi-dimensional detectors.

[0093] In the embodiments according to Figures 1A and 1B, the desired location of the optical coupling point 11 is achieved by the spatially resolved distribution of the captured light radiation within the capture region 130, which is determined using a measuring device 110. This is accomplished using an evaluation device 150 configured to determine the location of the optical coupling point 11 based on the spatially resolved distribution of the captured light radiation.

[0094] In the embodiment according to FIG. 1B, light provided by light source 112 for generating optical radiation is emitted into production area 120 using optical system 111. For this purpose, an objective lens (particularly preferably a photolithography objective lens) can preferably be used, which in each case affects the generation of optical radiation in the focusing cone 60 or only at the focal point 61 or in the volumetric elements surrounding the focal point 61 within production area 120. In this embodiment, the spatially resolved distribution of captured optical radiation in capture area 130 is achieved by optical coupling point 11, which captures the optical radiation generated in production area 120, assuming that the optical radiation can be coupled into optical coupling point 11 using measuring device 110, which can be particularly embodied in the form of a power detector and can additionally or alternatively include a camera sensor or detector array. In this case, the interaction area 15 of the optical coupling point and the capture area 130 are preferably congruent, at least in the vicinity of the coupling point. At a greater distance from the coupling point, it is possible that the light radiation generated at the point belonging to the interaction region 15 does not reach the optical coupling point 11, or only reaches the optical coupling point 11 with a large loss, because the absorption or scattering of the light radiation between the relevant point and the optical coupling point 11 is too great.

[0095] In the embodiment shown in FIG1B, the spatial resolution distribution of the captured light radiation in the capture region 130 is determined by the fact that the position of the focusing cone 60, the focusing point 61, or the associated volumetric element is preferably changed during the capture process using a beam scanner included in the optical system 111, for example in the form of a one-dimensional, two-dimensional, or three-dimensional scanning process within the production region 120, and the captured light radiation is continuously determined during this process using the measuring device 110. Data storage and evaluation, as well as the determination of the position and orientation of the optical coupling point 11, are achieved by means of an evaluation device 150 configured to determine the location of the optical coupling point 11 based on the spatial resolution distribution of the captured light radiation.

[0096] Regardless of the type of embodiment according to Figure 1A or Figure 1B, the light radiation or the light that generates light radiation is guided such that the light radiation or the light that generates light radiation actually passes through the optical coupling point 11. Only in this way can it be ensured that the spatially resolved distribution of the captured light radiation actually indicates the location of the optical coupling point 11, because the captured light radiation is associated with the optical coupling point 11 to be located.

[0097] The positioning of the optical coupling point 11 may include an indication of its position 13 and orientation 14, which is schematically shown in FIG. 2 together with the interaction region 15 of the optical coupling point 11. In this case, the indication of the spatial position 13 of the optical coupling point 11 may include a position vector in a three-dimensional coordinate system 30, while the indication of the orientation 14 of the optical coupling point 11 may include one or more three-dimensional orientation vectors, one of which indicates, for example, the direction from which light may be emitted from the optical coupling point 11, or the direction from which light may be effectively input into the optical coupling point 11. Particularly preferably, both the position vector and the orientation vector are represented in the same coordinate system 30. In the case of multiple orientation vectors, one of the orientation vectors may define the direction of rotation of the coupling point relative to the optical axis, the direction of rotation being determined, for example, by the polarization of the light emitted from or thereby captured by the coupling point.

[0098] The position 13 and orientation 14 of the optical coupling point 11 are determined using an evaluation device 150, preferably by at least one of the following measures. A first measure may include verifying the appearance or disappearance (particularly abrupt appearance or disappearance) of the light radiation captured at the location within the capture region 130. A further measure may include the capture distribution, such as the rise or fall of the spatially resolved distribution of the light radiation captured in the capture region. To generate light radiation, a further measure may include applying the model for the optical coupling point 11 to the input coupling of the light radiation input in the production region 120 to the location-related input of the optical coupling point 11, or to the distribution of light emitted from the optical coupling point 11. However, further measures are conceivable. In a very simple case, such a model may be based on so-called Gaussian beam theory, for example, assuming a paraxial approximation of beam propagation. Other models may use methods of Fourier optics or numerical descriptions of light field propagation.

[0099] Figure 3 schematically illustrates another exemplary embodiment of the method, wherein the spatial position 13 and orientation 14 of the coupling point 11 included in the optical component are captured by exciting or capturing luminescent radiation 21 in a volumetric element surrounding a focal point 51 of a beam 50 received or emitted from an objective lens 70. Spatial displacement of the volumetric element around the focal point 51, particularly by using a beam scanner, enables the determination of a spatially resolved distribution of the captured light radiation within a capture region 120, which is at least partially filled with a medium 19. In a preferred embodiment, the objective lens 70 can also be used to photolithographically produce microstructures. In a preferred embodiment, the capture region 120 may be at least partially filled with a material 20 configured to generate luminescence, which acts as part of the medium 19. This may include, for example, a photoresist that has exhibited multiphoton fluorescence under radiation below a polymerization threshold. In the simple case of an optical waveguide 12 having a surface perpendicular to the waveguide axis, the orientation 14 of the optical coupling point 11 corresponds to the optical axis of the portion of the optical waveguide 12 adjacent to the optical coupling point 11. In this case, the luminescent radiation 21 can be excited by the optical coupling point 11 or by the photolithography objective 70.

[0100] Figure 4 schematically illustrates another exemplary embodiment of the method, wherein the spatial position 13 and orientation 14 of the coupling point 11 included in the optical component is captured by exciting or capturing scattered radiation 26 in the volumetric element surrounding the focal point 61 of the light beam 60 received or emitted from the objective lens 70. This also applies to the description of Figure 3 regarding the spatial distribution of the volumetric elements, particularly in the case of one-dimensional or multi-dimensional scanning processes. Here, in a preferred embodiment, the objective lens 70 can also be used to photolithographically generate microstructures. Scattered radiation 26 can preferably be generated using a scattering center 27 that scatters light radiated into the volumetric element 61, such that the resulting scattered radiation can be at least partially captured. In the simple case of the optical waveguide 12, the orientation 14 of the optical coupling point 11 corresponds to the optical axis of the portion of the optical waveguide 12 adjacent to the optical coupling point 11. In this case, scattered radiation 21 can be excited by the optical coupling point 11 or using the photolithographic objective lens 70.

[0101] In another embodiment according to FIG. 5, the optical coupling point 11 is not located on the surface of the optical component 10, but is arranged, as an example, at a distance d offset from the surface of the optical component 10. This can occur, for example, with the face of the waveguide 12 offset by a distance d relative to the chip edge 18. In this case, the apex of the conical spatial region 15 is located within the optical component 10. In this case, the medium 19 is in direct contact with the surface of the optical component 10. In this case, the position of the chip edge 18 relative to the optical coupling point 11 can be determined due to the sudden disappearance or sudden drop in light radiation captured at the chip edge 18.

[0102] Figure 6 illustrates another exemplary embodiment in which the position 13 and orientation 14 of the optical coupling point 11 formed by the waveguide 12 of the optical component 10 are captured by stimulating the luminescent radiation 21 in the waveguide core 17 of the waveguide 12 itself. In this case, the waveguide core 17 preferably includes a material configured to generate the luminescent radiation 21. Additionally or alternatively, the waveguide core 17 may include another material (not shown) configured to generate scattered radiation.

[0103] Figures 7 and 8 schematically illustrate the microstructure 100 generated by the method, which is used to generate a microstructure at an optical coupling point and align it with the optical coupling point 11, the alignment being precise in position 13 and direction 14.

[0104] Figure 7 shows a microstructure 100 generated at position 13 of the optical coupling point 11, which takes the form of a dielectric free waveguide 101, also known as a "photonic wire bond", with the dielectric free waveguide 101 aligned with position 13 and orientation 14 of the optical coupling point 11.

[0105] Figure 8 illustrates a further microstructure 100 in the form of a microlens 102, located at a further optical coupling point 211 formed by a further optical waveguide 212 of a further optical component 210, which is not in direct contact with the already captured optical coupling point 11 included in the optical component 10. In this case, the position 213 and orientation 214 of the further optical coupling point 211 can also be used for the configuration of the microstructure 100. The microstructure 100 is configured based on the positions 13, 213 and orientations 14, 214 of the two optical coupling points 11, 211, thereby creating effective coupling between the two optical coupling points 11, 211. In addition to the exemplary embodiment according to Figure 8, it is also advantageous to generate the microstructure 100 at the two optical coupling points 11, 211 for effective coupling, the position and orientation of the two optical coupling points 11, 211 being used for the configuration of each microstructure 100.

[0106] Figure 9 illustrates another exemplary embodiment, in which a plurality of optical coupling points 11 are defined by the surfaces of waveguide cores 12 of a multi-core optical fiber. For example, in this embodiment, the optical radiation coupled to all fiber cores can be determined globally by a common measuring device 110, the effective area of ​​which extends to all waveguide cores of the multi-core optical fiber.

[0107] Figure 10 schematically illustrates various preferred embodiments for capturing optical radiation introduced into the optical coupling point 11 of the optical component 10, or for coupling light suitable for exciting optical radiation in the interaction region 15 of the optical coupling point 11. However, other embodiments not shown here are also possible.

[0108] For this purpose, in the embodiment according to FIG10A, the optical component 10 may include a light source 112 or a measuring device 110 having an optical connection to the optical coupling point 11 to be located.

[0109] For this purpose, in the embodiment according to FIG10B, the light source 112 or measuring device 110 may be arranged outside the optical component 10 and include a connection between the light source 112 and the optical component 10, preferably in the form of an optical waveguide or optical fiber.

[0110] In the embodiment according to FIG. 10C, the optical component 10 may have a coupling structure 113 (e.g., in the form of a so-called grating coupler) through which light or captured light radiation can be coupled out of or into the optical component 10. In this case, the coupled-in light or coupled-out light radiation can be captured or provided by the photolithography objective 70 itself, by another objective (not shown), or by another optical element (preferably an optical fiber) or a light source (preferably a photodiode (not shown)). In this case, the grating coupler can be designed to have high coupling efficiency for the wavelength of the light transmitted in the context of this method or the wavelength of the associated light radiation, while not affecting or significantly affecting the optical signal at the operating wavelength of the optical component 10.

[0111] In the embodiment according to FIG10D, the scattered or emitted radiation occurring within the waveguide 12 can preferably be captured by using the objective lens 70 itself or by using another objective lens. The generation of scattered radiation can be achieved here by a suitable scattering structure (e.g., based on a periodic structure). These structures can be designed to have high scattering efficiency for the wavelength of light transmitted in the context of this method, while not affecting or significantly affecting the optical signal at the operating wavelength of the optical component 10.

[0112] Figure 11 illustrates, by way of example, the interaction region 15 of the surface-illuminated photodiode 105. In this case, the optical coupling point 11 corresponds to the effective region 106 of the photodiode 105, and the normal vector of the effective region 106 of the photodiode 105 is generally considered to be the direction of the optical coupling point 11.

[0113] Figure 12 schematically illustrates a preferred exemplary embodiment of a device 200 according to the invention for positioning an optical coupling point 11 in an optical component 10 arranged on an optical stage 108 configured to be movable in the x, y, and z directions. The device 200 is based on a three-dimensional laser lithography system having rapid beam deflection by a beam scanner 132 (preferably in the form of a so-called "galvanometer scanner"), which has been extended by additional detection channels for optical radiation. In this case, the light source 112 comprises a femtosecond laser emitting a wavelength of 780 nm, a pulse duration of approximately 100 fs, and a repetition frequency of approximately 100 MHz. To implement the method for positioning the optical coupling point 11, fluorescence radiation 21 is generated using multiphoton excitation, with the excitation light partially radiated into the production region 120 through the beam path of the lithography system. In this configuration, the light used for excitation can be generated by the same light source 112 also used for the photolithography structure, or by an additional light source that can be coupled into the beam path via a separate beam splitter (not shown). The medium 19 used herein is a photoresist, and a fluorescent dye can be additionally mixed with the photoresist. To locate the optical coupling point 11, the selected parameters (particularly the power, wavelength, and / or pulse duration of the light radiated into the medium 19) are set such that the resulting dose is preferably still below a dose threshold relative to unwanted polymerization during detection. In this configuration, a portion of the fluorescent radiation 21 generated within the production region 120 is coupled into the optical coupling point 11. In this exemplary embodiment, the optical components include at least one optical waveguide 12, for example in the form of an optical fiber, which includes at least one waveguide core 17. The waveguide 12 is connected to a measurement device 110, which may be implemented herein as a photomultiplier tube, and the measurement device 110 quantitatively captures the fluorescent radiation 21 coupled into at least one waveguide core 17 in a manner dependent on the spatial location of the focal point of the photolithography system used for excitation. In the case of multi-core optical fibers, according to Figure 9, by using a measurement device 110 in the form of a photomultiplier tube, all the fluorescence radiation 21 coupled into each waveguide core 17 can be captured as a whole.

[0114] Alternatively, a light source 112 suitable for exciting light radiation can be connected to at least one of the waveguide cores 17 (not shown). The light radiation is then captured by the objective lens 70 and fed to a further measuring device 110' in the form of a photomultiplier tube via a means referred to as fluorescence path 115. In this embodiment, the entire fluorescence path 115 is formed by the objective lens 70 and its upstream lenses and beam splitters, and may additionally include a beam scanner 132. The time-resolved signals of the measuring devices 110, 110' are digitized. Based on the focal positions in all three spatial directions (which are set using the beam scanner 132 and are therefore known), the captured light radiation can be determined in a spatially resolved manner, and the orientation and position of at least one waveguide core 17 can be determined thereby.

[0115] In addition, as schematically shown in FIG12, the device 200 may include additional optical, optoelectronic or electronic components, particularly additional measuring device 110, light source 112, lens, mirror, beam splitter or filter.

[0116] The apparatus 200 was successfully used to measure the position 13 and orientation 14 of the optical coupling point 11 in single-core and multi-core optical fibers. An exemplary embodiment aims to identify the coupling point 11 of a seven-core optical fiber. Compared to conventional single-core fibers, multi-core fibers are not symmetrical with respect to arbitrary rotations around the fiber axis, thus the position 13 of the waveguide cores 17 after installation is typically uncertain. To detect the waveguide cores 17, multiphoton fluorescence radiation is excited using a lithography objective 70 disposed in a volume upstream of the end face of the multi-core fiber, providing a measurement device 110 to capture the multiphoton fluorescence radiation across all seven waveguide cores 17, the measurement device 110 being connected to the multi-core fiber in the form of a photomultiplier tube. To measure the spatially resolved distribution of the fluorescence radiation, the excited beam is first moved laterally within the focal plane of the lithography objective 70 using a beam scanner 132. Furthermore, the focal plane itself is moved relative to the optical multi-core fiber by means of the objective driver 135 utilizing the axial displacement of the objective in the z-direction. The positions 13 and orientations 14 of the optical coupling points 11 assigned to each waveguide core 17 can be determined from the three-dimensional spatially resolved distribution of the fluorescence radiation captured by the multi-core optical fiber. Furthermore, a portion of the excited fluorescence radiation can be captured by the photolithography objective 70 itself and used for imaging purposes. In this respect, the recorded measurement data in the evaluation apparatus 150 can be used both to determine the topology of the optical component 10 and to achieve precise determination of the positions 13 and orientations 14 of the optical coupling points 11.

[0117] The apparatus shown in Figure 12 can also be used in a slightly modified form to achieve a method for generating microstructures (not shown here) at the optical coupling point 11. For this purpose, parameters (particularly the wavelength, power, or pulse duration of the light emitted by the light source 112) can be varied to enable the polymerization of the photoresist in spatial elements near the focal point of the photolithography beam. By using the movement of the focal point and the simultaneous variation of the incident light, spatially selectively solidified volumetric regions can be generated, which collectively form the desired microstructure. In this case, polymerization can be based on a single-photon or multi-photon absorption process. In one particular embodiment, the light source may include a femtosecond laser, the output power of which can be varied directly or by using an external modulator (preferably an acousto-optic modulator). Furthermore, the light source may include an adjustable pulse compressor that makes it possible to vary the pulse duration of the light radiated into the photoresist.

[0118] In the representation of the two-photon fluorescence power distribution, the two-photon fluorescence power is verified using a multi-core fiber located in the plane of the central waveguide core 17 perpendicular to the z-direction (which corresponds to the direction along the optical axis of the lithography objective 70). Since it is impossible to excite two-photon fluorescence within the optical component 10, the fluorescence may suddenly drop at the transition between the medium 19 and the fiber surface. In this case, the sudden drop in captured light radiation can be used to precisely locate the fiber surface serving as the optical coupling point 11. By recording a large number of images at different z-positions, it is possible to achieve three-dimensional spatially resolved capture of two-photon fluorescence in volume. As a result, a virtual cross-section in the plane perpendicular to the axis of the multi-core fiber also becomes possible, in which the seven cores of the multi-core fiber are clearly identifiable. In this case, it is particularly noteworthy that the cross-section of the fiber core can be precisely derived directly from the distribution of the emitted radiation 21 at the optical coupling point 11. Furthermore, the spatial distribution of the luminescent radiation 21 captured by the lithography objective 70 itself can be similarly captured in an image stack consisting of different focus levels, from which the topology of the optical fiber can be identified, but the position 13 of the corresponding coupling point 11 cannot be identified.

[0119] List of reference numerals

[0120] 10, 210 Optical components

[0121] 11, 211 Optical coupling points

[0122] 12,212 Optical waveguide (fiber), which is related to the coupling point.

[0123] Location of coupling points 13 and 213

[0124] 14, 214 Direction of coupling points

[0125] 15. Interaction region of coupling points

[0126] 16 Points in the overlapping region

[0127] 17 waveguide core

[0128] 18 Chip Edge

[0129] 19. Medium (Interactive Medium)

[0130] 20 substances configured to produce light emission

[0131] 21. Luminous radiation (fluorescent radiation)

[0132] 25 substances configured to produce scattering

[0133] 26. Scattered radiation

[0134] 27 Scattering Center

[0135] 30 Coordinate System

[0136] 40 Microstructures

[0137] 50. Focused laser beam used to generate light emission

[0138] 51 Focus

[0139] Imaging focal cone of 60 lithography objective lens

[0140] 61 Focus

[0141] 70 Objective lens (lithography objective lens)

[0142] 100 microstructures

[0143] 101 Aligned Dielectric Waveguide

[0144] 102 Aligned microlenses

[0145] 105 Surface Illumination Photodiode

[0146] 106 Effective area of ​​surface-illuminated photodiode

[0147] 108 Optical Observation Station

[0148] 110, 110' measuring device

[0149] 111 Optical systems used to generate or capture light radiation

[0150] 112 Light Source (Pulsed Light Source)

[0151] 113 Coupled Structure

[0152] 114 Waveguide Scattering

[0153] 115 Fluorescence Pathway

[0154] 120 light radiation capture area

[0155] Production area with 130 light radiation

[0156] 132 beam scanner

[0157] 135 Lens Driver

[0158] 150 Evaluation Device

[0159] 200 Device for locating optical coupling points

Claims

1. A method for locating an optical coupling point (11), comprising the following steps: a) Provide an optical component (10) including an optical coupling point (11), wherein the optical coupling point has an interaction region (15) located outside the volume surrounded by the optical component (10); b) Light radiation is generated in the production area (120), wherein the production area (120) overlaps at least partially with the interaction area (15) of the optical coupling point (11), wherein light is irradiated on a medium (19) located in the production area (120), the medium (19) altering the light to generate light radiation; c) Capturing at least a portion of the generated light radiation in the capture region (130), wherein the capture region (130) at least partially overlaps with the interaction region (15) of the optical coupling point (11), and determining the spatially resolved distribution of the captured portion of the generated light radiation; and d) Determine the location of the optical coupling point (11) based on the spatially resolved distribution of the captured portion of the generated light radiation. At least a portion of the generated light radiation is captured through the optical coupling point (11).

2. The method according to claim 1, wherein the medium (19) comprises a scattering center (27), a luminescent material (20) or a photoinitiator forming the luminescent material (20), wherein the scattering center (27) generates scattered radiation (26), or wherein the luminescent material (20) generates luminescent radiation (21).

3. The method according to claim 2, wherein the luminescent radiation (21) is generated by exciting a multiphoton absorption process in the luminescent material (20).

4. The method according to claim 2 or 3, wherein the medium (19) further comprises a photoresist, wherein a dose below a dose threshold of the polymerization of the photoresist is introduced into the photoresist to generate light radiation.

5. The method according to claim 1 or 2, wherein light radiation is captured by an objective lens (70) or light used to generate light radiation is irradiated into a production area (120), wherein the objective lens (70) has a numerical aperture of at least 0.

3.

6. The method according to claim 1 or 2, wherein the radiation of light entering the production area (120) or the capture of light radiation generated in the capture area (130) is spatially varied, and wherein the spatially resolved distribution of the captured light radiation is captured through the optical coupling point (11).

7. The method according to claim 6, wherein spatial variation of the radiation of light entering the production area (120) or capture of the light radiation generated in the capture area (130) is achieved by using a beam scanner (132).

8. The method according to claim 1 or 2, wherein the positioning of the optical coupling point (11) includes the indication of the position (13) and orientation (14) of the optical coupling point (11), wherein the position (13) and orientation (14) of the optical coupling point (11) are determined by at least one of the following measures: Verify the presence or absence of captured light radiation at a location within the capture area (130); Evaluate the spatially resolved distribution of the captured portion of the light radiation generated in the capture region (130); In order to generate light radiation, the model for the optical coupling point (11) is applied to the input coupling related to the location of the light radiation input from the production area (120) to the optical coupling point (11), or to the distribution of light emitted from the optical coupling point (11).

9. A method for generating a microstructure (100) at an optical coupling point (11) of an optical component (10), comprising the steps of: i) Positioning the optical coupling point (11) according to the method of claim 1 or 2; and ii) A microstructure (100) is generated at the optical coupling point (11) by using a manufacturing method selected from additive manufacturing method or subtractive manufacturing method.

10. The method of claim 9, wherein the objective lens (70) is used to locate the optical coupling point (11) and to generate a microstructure (100) at the optical coupling point (11), wherein the objective lens has a numerical aperture of at least 0.

3.

11. A device (200) for locating an optical coupling point (11), comprising: An optical component (10) includes at least one optical coupling point (11), wherein the optical coupling point has an interaction region (15) located outside the volume surrounded by the optical component (10); An optical device configured to generate light radiation in a production area (120) or capture at least a portion of the generated light radiation in a capture area (130), wherein the production area (120) and the capture area (130) at least partially overlap with the interaction area (15) of the optical coupling point (11); and An evaluation device (150) is configured to determine the spatial resolution distribution of the captured portion of the light radiation and, based on the determined spatial resolution distribution of the captured portion of the light radiation, determine the position of the optical coupling point (11). The device (200) is configured to capture at least a portion of the generated light radiation through the optical coupling point (11).

12. The apparatus (200) according to claim 11, wherein the optical device includes a light source (112) configured to generate light, which, when irradiated onto a medium (19) located in the production area (120), alters the light to generate light radiation.

13. The apparatus (200) according to claim 11 or 12, wherein the optical apparatus further comprises a beam scanner (132) configured to achieve spatial variation of the radiation of light entering the production area (120) or to achieve spatial variation of the light radiation generated in the capture area (130).

14. The device (200) according to claim 11 or 12, wherein the optical device is further configured to generate a microstructure (100) at the optical coupling point (11).

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