OPTICAL FIBER CONNECTOR AND ADJUSTMENT METHOD

Description

[0001] The invention relates to an optical fiber connector and a method for adjusting the fiber connector.

[0002] Modern imaging systems, especially those for three-dimensional (3D) imaging in microscopy, require a stable coupling of the radiation used for illumination. Since spatial decoupling of the light source and the microscope system is often advantageous, the delivery of the radiation using light-conducting fibers, such as polarization-maintaining single-mode fibers, has become established. The adjustment-free connection of a polarization-maintaining single-mode fiber to any microscope system is a major advantage in terms of flexible use and simplified maintenance.

[0003] A fiber optic connector with a plug and a socket is already known from DE 1 961 104 U. The plug is shaped like a truncated cone and surrounds the optical fiber at one end. The socket is shaped to complement the plug. The plug and / or the socket can be made of a ferromagnetic material or a magnetically influenced material and attract each other. Centering of the plug and socket relative to each other is achieved through a complex and very precise manufacturing of the contact surfaces of the connector.

[0004] Another connector for transmitting electrical and optical data between a plug and a socket is described in US 2010 / 0080563 A1. To improve transmission reliability, lenses and collectors can be arranged in the optical fiber paths to collect the transmitted light.

[0005] To transmit laser light from a light-conducting fiber into another optical system, an optical connector for optical fibers, such as that disclosed in DE 10 2007 051 294 A1, is suitable. A connector of the connector has several connector parts, one of which serves to receive an end of an optical fiber enclosed in a socket.

[0006] Another is provided with a lens, with a means for aligning and fixing the end of the optical fiber along a beam direction, and with a means for aligning the lens perpendicular to an optical axis of the lens. A third plug part has at least one contact surface and is connected to the first and / or second plug part. A corresponding socket of the optical connector has a centering ring for aligning the plug in a plane perpendicular to the beam direction. Manual adjustment of the angle of the emerging beam is possible within limits by laterally shifting the fiber and the lens relative to each other. The final angular accuracy of the emerging collimated beam is achieved iteratively by mechanically machining four existing support feet. This results in an individual adaptation of a plug to a socket.The female counterpart has a polished contact surface that introduces only minimal additional angular error. The connection between the male and female connectors is achieved by a rotating movement of the male connector and its contact with a polished surface. The male connector is held in place by a combination of projections and springs. Disadvantages include wear caused by the rotational connection movement and the complex, customized manufacturing process, which requires iterative optimization.

[0007] Other solutions, such as those described in US Pat. No. 6,276,843 B1, leave the alignment elements permanently in the system. Since the collimation optics in the fiber cylinder cannot be adjusted relative to the fiber end, the location and angle must be readjusted when changing the fiber to maintain the required accuracy.

[0008] US 2001 / 0046345 A1 discloses a single-channel MXN optical fiber switch.

[0009] The invention is based on the object of proposing an improved fiber connector. It is also an object of the invention to propose an improved alignment method.

[0010] The object is achieved with regard to the optical fiber connector with a fiber connector according to claim 1. Advantageous developments of the invention are the subject of the dependent claims.

[0011] The fiber connector is designed for optically coupling a light-conducting fiber to the connector receptacle and comprises a connector housing for receiving and locking components of the fiber connector in a predetermined relative position to one another. The connector housing has a fiber input and a fiber support for stationary reception of the light-conducting fiber. Optically downstream of the fiber support along a beam path is at least one optical lens for collecting light emerging from an end face of the light-conducting fiber and for collimating the collected light. Furthermore, the connector housing has a coupling surface with an output of the beam path and with a coupling structure for connection to a reception structure complementary to the coupling structure.

[0012] According to the invention, at least one adjustable optical element is arranged in the beam path, optically downstream of the fiber bearing, in addition to the at least one optical lens. In one possible embodiment of the fiber connector, the optical lens is also adjustable. The coupling structure of the fiber connector according to the invention comprises a first component of a kinematic coupling and a first component of a magnetic coupling consisting of two components.

[0013] The optical path of the fiber connector is determined by a theoretical path, provided for by the design of the fiber connector, that light radiated from a fiber into the fiber connector takes to an optical output of the fiber connector at the coupling surface. The optical path is essentially determined by a virtual axis along which the optical axis of the finally adjusted optical lens is aligned.

[0014] The light transmitted via the optical fiber is in particular laser light, which can optionally be polarized.

[0015] The kinematic coupling can be designed according to the so-called Maxwell principle. For example, three V-shaped grooves are aligned at an angular distance of 120° towards a common virtual intersection point and combined with three matching curved support surfaces as counterparts. The kinematic coupling ensures that all six spatial degrees of freedom are defined. The corresponding elements are appropriately distributed between the fiber connector and connector receptacle. For manufacturing reasons, pairs of rods or half-rods with, for example, round, rounded, or square profiles can be used instead of the V-shaped grooves. The corresponding complementary counterstructures can be, for example, rods, half-round rods, spheres, or spherical segments. The rods, half-rods, spheres, or spherical segments can be made of, for example, steel, a metal alloy, ceramic, or a suitably wear-resistant plastic.Other designs also allow for different angular spacings. For example, the elements of the kinematic coupling can be arranged at an angle of 80° and two angles of 140° each. Other angle combinations totaling 360° are also possible. Instead of the V-shaped grooves, differently designed elements of the kinematic coupling can also be used.

[0016] The magnetic coupling is implemented, for example, by means of at least one ring magnet as the first and / or second component. The ring magnet can surround the optical output of the beam path from the connector housing, in particular centrally and / or rotationally symmetrically. This advantageously achieves centering of the fiber connector, in particular the output of the beam path, relative to the connector receptacle and a beam feedthrough present therein.

[0017] In further embodiments of the fiber connector, the first component of the magnetic coupling can be divided into several sections. The same applies to a connector receptacle (see exemplary embodiments). If the first and second components are designed as magnets, they are arranged with opposite polarity. In alternative embodiments, the ring magnet or the sections of the ring magnet(s) can be arranged asymmetrically around the output or a passage in the connector receptacle. What is relevant here is that the interaction of the first and second components of the magnetic coupling results in a centering of the output of the fiber connector to a passage of the connector receptacle via the elements of the kinematic coupling.

[0018] If only one of the components is a magnet, the corresponding other component contains a magnetically influenced material. In a simple and efficient embodiment, the material is iron. In other designs, the material can be an iron-containing alloy or an iron-containing composite or plastic. The magnetically influenced material can be present over the entire surface, divided into partial surfaces, and / or embedded in a carrier material. Embedding it, for example, in a suitable plastic, protects the material from unwanted chemical reactions, such as corrosion.

[0019] The fiber connector according to the invention, in conjunction with a connector receptacle described below, enables a self-centering and positionally stable plug connection. Individual mechanical adjustments are dispensed with, even when different fiber connectors and connector receptacles are combined. A twist-proof design ensures that an optical polarization axis remains unchanged and linearly polarized light is transmitted in a predetermined orientation. The centering and positioning of the fiber connector and connector receptacle relative to one another is advantageously achieved by the kinematic coupling, while the required holding force and centering are generated by the action of the magnetic coupling. This enables easy-to-handle, flexible, and reproducible production and use of a plug connection without wear.The optical connector design, which is protected against unwanted twisting, is achieved, for example, by the kinematic coupling.

[0020] If the components of the kinematic coupling are arranged asymmetrically in an alternative embodiment, for example, not all at a 120° angle to each other and / or with different radial distances, the fiber connector can only be connected to the connector receptacle in a single relative position. For example, such a design allows the definition and maintenance of the position of a polarization direction (oscillation plane of the E vector) when using linearly polarized light.

[0021] Precise and reproducible production of the connector is an essential prerequisite for the adjustment freedom of the connector according to the invention. To ensure that the position of the beam, especially the collimated beam, is precisely adjusted with each subsequent connection, the fiber connector can have adjustable optical elements that remain in the adjusted state after a single adjustment. Therefore, readjustment during a subsequent connection is not necessary. Optionally, the adjustable optical elements can be permanently locked in the adjusted state.

[0022] As shown schematically in Fig. 1a and 1bAs shown, there are essentially two possible errors in the alignment of a fiber ferrule 10 of a light-conducting fiber 1 relative to the collimation optics 2 (optical lens 2). The fiber ferrule 10 or ferrule 10 encompasses the end of the fiber 1 in a known manner. The end at which the light guided by the fiber 1 exits is arranged in a focal plane of the optical lens 2.

[0023] In the first case, the ferrule 10 is not or not exactly located on the optical axis 3 of the lens 2, but is aligned parallel to it ( Fig. 1a ). The end of fiber 1 is not at the focal point, but in the focal plane of optical lens 2. Due to this parallel offset, an angular error occurs in the infinity beam path behind optical lens 2.

[0024] If, on the other hand, the ferrule 10 is inclined relative to the optical axis 3 of the lens 2, i.e. the radiation from the fiber 1 hits the optical lens 2 at an angle, this leads to a spatial offset in the collimated beam behind the lens 2 ( Fig. 1b ). In the graphic representation of this situation, the main ray is tilted, but its origin is at the focal point.

[0025] If the fiber end, i.e. the beam exit from the fiber 1, is located in the focal plane or in the focus point of the optical lens 2, the optical lens 2 causes a collimated beam (image to infinity / infinity beam) after the radiation has passed through the optical lens 2. Fig. 1a and 1b ). Under this condition, the angle and spatial offset can be adjusted separately. Therefore, the fiber connector according to the invention has at least one adjustable optical element by means of which the angular position and / or the spatial offset can be adjusted.

[0026] The fiber is advantageously enclosed at its end by the ferrule, which in turn can optionally be surrounded by a sleeve and which is held in the fiber connector, for example in a fiber bearing. The sleeve is, for example, a slotted ceramic tube that allows the ferrule to be clamped without exerting pressure on the fiber. To reduce back reflections in the fiber, the end can be beveled at an angle of, for example, 8°. Such a bevel must be taken into account when integrating the fiber. The fiber is advantageously provided with a strain relief device to ensure secure hold of the fiber in the fiber connector and permanently high reproducibility of the mating process and light transmission.

[0027] In one possible embodiment of the fiber connector, a pair of prism wedges with two mutually adjustable prism wedges (a so-called Risley pair; see, for example, US 6,859,120 B2 and US 4,515,447 A1) serves as the adjustable optical element. The prism wedges are independently rotatable about an axis parallel to the optical axis. Additionally or alternatively, the prism wedges can be tilted about multiple axes. The angle and spatial offset can be adjusted using the tiltable pair of prism wedges.

[0028] In a further embodiment of the fiber connector according to the invention, a pair of pivoting wedges can be provided as an adjustable optical element for adjusting the beam path. This pair comprises two lenses whose opposite side surfaces are designed as flat surfaces and which can be tilted and / or laterally displaced relative to one another. For example, one of the lenses is designed as a plano-concave lens and the other lens as a plano-convex lens. The concave and convex side surfaces are advantageously adapted to one another in terms of their size and curvature so that they engage with one another directly or with only a small gap between them and can nevertheless be moved relative to one another, in particular tilted and / or displaced. In further embodiments of the fiber connector, the pair of pivoting wedges can be tilted and locked as a whole.

[0029] In a further embodiment, at least one plane-parallel plate (plane plate, plate) is arranged as an adjustable optical element. This plate can be tilted relative to the beam path of the fiber connector about at least one axis and by a tilt angle. If this plane plate is located in the section with a divergent beam path, the angle is ultimately adjusted by the action of the at least one plane plate. If, on the other hand, the plane plate is arranged in the section with a collimated beam path, the spatial offset is ultimately adjusted by a change in position, in particular by a change in the inclination (tilt angle). The plane plate is particularly advantageously designed in the form of a spherical base body with two mutually parallel side surfaces (e.g., US Pat. No. 8,254,735 B2; "window ball"). By tilting about two axes orthogonal to the beam path, spatial offsets can be corrected in two lateral degrees of freedom.

[0030] For the embodiment described above, it is possible for an additional plane-parallel plate and / or an additional pair of mutually adjustable prism wedges to be arranged in the beam path. If at least one plane plate and one prism wedge or one pair of prism wedges (a pair of rotating wedges with identical wedge angles) are present, the adjustment of the spatial offset and the angle is possible. Two or more plane plates allow a more variable response to the current angles or spatial offsets. For example, if two plane plates are used, they are arranged with opposing tilt angles or can be adjusted with the corresponding tilt angles.

[0031] In further possible embodiments of the fiber connector according to the invention, the plane plate or plane plates can be omitted if the aforementioned pair of prism wedges is arranged in a common mount, which allows the adjusted wedges to be additionally tilted in two axes to achieve a parallel offset of the beam. If the jointly mounted pair of prism wedges (rotary wedge pair) is located in the area of ​​a collimated beam path, the prism wedges are brought into a so-called zero position (see also Fig. 7b), in which the optical effects of the two prism wedges cancel each other out. In this way, when the pair of prism wedges is tilted together, an optical effect corresponding to the tilting of a plane plate is achieved. The spatial offset can then be adjusted by tilting the pair of prism wedges in the zero position, and the pair of prism wedges can be fixed in this tilted position. The degree of tilt depends, among other things, on the orientation of the plane surfaces—namely, either facing towards or away from each other—and on the wedge angle of the prism wedges.

[0032] If prism wedges or pairs of prism wedges are used, chromatic correction of the prism wedges is required if the optical connector is intended to be used over a broad wavelength range, particularly the visible range (VIS, approx. 400–700 nm, preferably up to 645 nm; in other versions up to 800 nm). For this purpose, materials are combined appropriately with respect to their refractive index and Abbe number (dispersion properties), with the prism angle being adjusted to the refractive index to achieve a suitable total deflection while maintaining sufficient sensitivity. A suitable glass combination for an achromatic prism is, for example, N-FK5 and F2 (both from SCHOTT ADVANCED OPTICS).

[0033] The optical lens and, if present, the lenses of the pivoting wedge pair can also be chromatically corrected with regard to the wavelengths intended for use. In a further embodiment of the fiber connector, the prism wedges can be omitted if the optical lens can be adjusted orthogonally to the beam path (x-direction or y-direction) in addition to being moved along the beam path (z-direction) and if the optical lens can also be tilted relative to the beam path about axes in the x-direction and y-direction (tilt angle Phi x or Phi y ). In this embodiment, at least one plane plate is present in the beam path and serves to correct any residual errors that still exist. This embodiment requires a minimal number of optical elements.

[0034] A light-conducting fiber can be inserted and held in the fiber storage. A light exit surface of the fiber is aligned along the beam path, meaning the optical axis or longitudinal axis of the fiber is aligned along the beam path of the fiber connector. Angular errors and / or spatial offsets may still occur, which can be corrected or are already corrected by appropriate adjustment of the at least one adjustable optical element. The fiber accommodated in the fiber storage can be held or is held in place by a clamping element present in the fiber storage.

[0035] In a finally adjusted state of the fiber connector, the adjustable optical elements are adjusted such that light emerging from the fiber is or can be provided at the optical output of the fiber connector parallel and symmetrical to the beam path. The adjusted beam is centered with respect to the kinematic coupling so that when the connection between the fiber connector and the connector receptacle is established, the light beam is or can be radiated from the fiber connector into an optical device carrying the connector receptacle in a predetermined orientation and, in the case of polarized light, possibly in a correct rotational position. To maintain this adjusted state, the adjustable optical elements can be permanently locked in this adjusted state.Such a non-releasable locking, which is not part of the invention, can be achieved, for example, by gluing, casting, soldering or welding the adjustable optical elements and optionally the optical lens.

[0036] The aforementioned connector receptacle for connecting to the fiber connector has a second component of the kinematic coupling, designed to complement the first component of the kinematic coupling, as a receiving structure. A second component of the two-component magnetic coupling is also present. Since the connector receptacle is advantageously designed to be essentially flat or plate-shaped, at least in the area of ​​the receiving structure and the second component of the magnetic coupling, the term "socket" or "plug socket" is not used.

[0037] The complementary design of the kinematic coupling ensures the correct relative position of the fiber connector and connector receptacle. The magnetic coupling provides the necessary holding forces without the need for mechanical components.

[0038] To prevent accidental interruption of the connection, the fiber connector and connector receptacle can be secured by means of a mechanical safeguard, for example by means of a force-free screw connection or a securing bracket.

[0039] In one version of the connector receptacle, an adjustable plane-parallel plate is arranged in its beam path. This type of connector receptacle allows for further adjustment of the required tolerance for the beam position of the fiber connector or connector connection. The plane-parallel plate in the connector receptacle can be adjusted relatively easily. This type of connector receptacle can be combined with all of the fiber connector versions described above.

[0040] An optical plug connection according to the invention comprises a fiber connector according to the invention in one of the embodiments described above and a connector receptacle or a fiber connector according to the invention and a connector receptacle having a second component of the kinematic coupling designed complementarily to the first component of the kinematic coupling located on the fiber connector as a receiving structure and a second component of the magnetic coupling consisting of two components.

[0041] The object is also achieved by a method for adjusting a fiber connector, which is defined in claim 11, wherein a fiber connector is used with a fiber inserted and aligned in the fiber bearing.

[0042] The method comprises aligning the fiber connector and its beam path relative to an external alignment device. The alignment device is then illuminated with light from the fiber connector. The adjustable optical elements are then adjusted until light emerging from the fiber is provided at the optical output of the connector housing, parallel and symmetrical to the beam path. In one embodiment of the method, the optical lens acting as a collimator can be moved in the direction of the beam path to adjust the beam propagation. The beam angle can be adjusted by moving the optical lens transversely to the beam path. The adjustment can be carried out, for example, using a measuring system such as a focusable autocollimation telescope (FAKF; a combination of an alignment telescope and (auto-)collimation telescope), which is focused accordingly to adjust the location or angle.Alternatively, the alignment can be performed using two separate beam paths with reference marks for location and angle and correspondingly adapted optics positioned upstream. Once the adjusted state of the adjustable optical elements in the fiber connector is reached, they are locked. Optionally, but not according to the invention, the adjustable optical elements can be permanently locked in the adjusted state, for example, by gluing, soldering, welding, or encapsulating them. In addition, the optical lens, especially if it is adjustable, and optionally the ferrule in the fiber bearing can be permanently locked.

[0043] The result is a monolithic fiber connector that can be pre-adjusted and plugged into different connector receptacles without the need for readjustment. The correct beam position is permanently ensured by the described adjustment process and the definition of the fiber connector components. The correct alignment of the fiber connector relative to the connector receptacle is achieved by a combination of kinematic and magnetic coupling. In this way, the interaction of the technical measures in the fiber connector and the measures for reproducible creation of the plug connection by means of the two couplings creates an optical plug connection that can be established without adjustment and reproducibly between any fiber connectors and connector receptacles according to the invention.

[0044] The advantages of the optical connector according to the invention and the adjustment method according to the invention include, for example, increased stability of the coupling against environmental influences overall and reduced effort and thus costs for installation, service, and maintenance of the systems. In particular, no complex readjustment of the beam position is necessary. Furthermore, screwing of the components and the permanent integration of adjustment aids in the fiber connector and the connector receptacle can be advantageously dispensed with. The repeatability of the connector is ideal due to the complete kinematic definition. It ensures minimal deviations in both the spatial position and the solid angle. Due to the symmetry of the arrangement, homogeneous expansion results when temperatures change, so that such a system has optimal stability properties in fluctuating ambient temperatures.Since the individual connectors must not exceed a certain limit with regard to mating repeatability, beam position, and beam angle, the present invention actively adjusts the individual connectors against a common external reference. Furthermore, the fixation via a central ring magnet optimally utilizes the self-centering properties of the kinematic coupling, enabling true plug & play. The accuracy in angle and position is not only achieved after screwing or clamping the components of the connector connection, but instantaneously during the mating process.

[0045] The invention simplifies the adjustment process and significantly reduces production time. Furthermore, assembly and / or adjustment can be partially or fully automated. In addition to the required precision, the proposed solution is particularly wear-resistant.

[0046] The invention can furthermore be connected to and used, for example, for the reproducible coupling and uncoupling of light from a single-mode fiber to a device system, for example to a microscope or to an interface of a microscope. The microscope can be, for example, a light-sheet microscope, a confocal microscope, a confocal scanning microscope, or a wide-field microscope. Other known uses, possibly subject to high precision requirements, include the coupling of a free beam into a single-mode or multimode fiber. Here, too, both the angle and the beam position must be stably corrected. In such a design, a socket can additionally be provided, by means of which active positioning relative to the free beam is possible. For example, use with a fiber permanently mounted to a microscope and adjustment-free plugging on the light source side is also possible.

[0047] The invention is explained in more detail below using exemplary embodiments and illustrations.

[0048] Showing: Fig. 1a shows a schematic representation of a resulting angular error; Fig. 1b shows a schematic representation of a resulting spatial offset; Fig. 2 shows a schematic representation of a first exemplary embodiment of an optical plug connection according to the invention with a fiber connector according to the invention and with adjustable optical elements in the infinite beam path; Fig. 3 shows a schematic representation of a second exemplary embodiment of an optical plug connection according to the invention with a fiber connector according to the invention and with adjustable optical elements in the infinite beam path, as well as a schematic representation of the interface to a microscope; Fig. 4 shows a schematic representation of a third exemplary embodiment of an optical plug connection according to the invention with a fiber connector according to the invention and with adjustable optical elements in the infinite beam path; Fig.5 shows a schematic representation of a fourth exemplary embodiment of an optical plug connection according to the invention with a fiber connector according to the invention and with adjustable optical elements in a divergent section of the beam path; Fig. 6 shows a schematic representation of a fifth exemplary embodiment of an optical plug connection according to the invention with a fiber connector according to the invention and with adjustable optical elements in a diverging section of the beam path and in the infinity beam path; Fig. 7a shows a schematic representation of a zero position of two mutually adjustable prism wedges and the resulting optical effect; Fig. 7b shows a schematic representation of two mutually adjusted prism wedges and the resulting optical effect; Fig. 8a shows a schematic representation of a pair of pivoting wedges in the zero position and the resulting optical effect; Fig.8b shows a schematic representation of the pair of pivoting wedges in a pivoted state and the resulting optical effect; Fig. 9 shows a schematic representation of an embodiment of a coupling surface of the connector housing of a fiber connector with first components of a kinematic coupling and with a first component of a magnetic coupling; Fig. 10 shows a schematic representation of an embodiment of an exemplary connector receptacle with second components of a kinematic coupling and with a second component of a magnetic coupling; Fig. 11 shows a schematic representation of a sixth embodiment of an optical connector according to the invention with a fiber connector according to the invention and with adjustable optical elements in the infinite beam path and with a plane-parallel plate in the beam path of the connector receptacle; Fig. 12 shows a schematic representation of an arrangement for adjusting a fiber connector; and Fig.13 a flow chart of an embodiment of an adjustment method according to the invention. .

[0049] The Figures 2 to 9 The illustrated embodiments are schematic representations. The reference numerals identify identical technical elements.

[0050] In Fig. 2 An arrangement of several optical elements in a beam path 6 is shown as an example. Furthermore, the resulting corrective effect of these optical elements is illustrated.

[0051] The fiber 1 enclosed in the ferrule 10 is aligned parallel to the optical axis 3, but offset from it. The beam path 6 and the optical axis 3 do not coincide in this section, ie, the beam path 6 runs parallel but offset from the optical axis 3. Without correction, a resulting angular error of the collimated beam would occur, as shown in Fig. 1ais shown. The light emerging from the end face of the fiber 1 diverges and strikes the optical lens 2, which acts as a collimating optic. Due to the action of the optical lens 2, the light is collimated and reaches an optical wedge or prism wedge 4 at an angle to the optical axis 3. This is designed or arranged with regard to its optical properties, in particular with regard to its light-refractive properties, and its relative position in the beam path 6, such that the rays of light run parallel to the optical axis 3 after passing through the prism wedge 4. As can be seen in particular from the central ray, a spatial offset may still be present. This is corrected by a plane plate 5, which is also located in the beam path 6. The plane plate 5 is inclined with respect to the optical axis 3 according to the spatial offset to be corrected and taking its optical properties into account.As a result, the light rays exhibit no angular error and no spatial offset with respect to the drawing plane after leaving the plane plate 5. Beam path 6 and optical axis 3 are symmetrical to each other and, in the example, coincide after the plane plate 5. The beam path 6 is now aligned along the optical axis 3. The light corrected in this way can be used at an interface 17 (see . Fig. 3 to 6 ) for further use. To achieve the desired corrective effect, the prism wedge 4 and the plane plate 5 are adjustable, for example, they can be rotated or tilted.

[0052] The Fig. 2 The principle shown is in a first embodiment of an optical connector according to the invention in Fig. 3 implemented.

[0053] A fiber connector 7 comprises a connector housing 8 with a fiber bearing 11 into which the fiber 1 is inserted. The incoming light is emitted from the fiber connector 7 at an output 9 of the connector housing 8. The fiber, gripped by the ferrule 10, is held stationary in the fiber bearing 11. After a section of the beam path 6 with diverging rays of light, the light strikes the optical lens 2 and is corrected for angular error and spatial offset by the action of the adjustable optical elements arranged downstream in the beam path 6. For simplicity, the beam path is divided into a section with diverging light rays and a section with collimated light rays.

[0054] In the in the Figures 3 and 4In the embodiments shown, the beam manipulation or correction takes place entirely in the infinity beam, i.e. in the section of the beam path 6 with collimated light beams. Fig. 3 In the first embodiment shown, instead of a single prism wedge 4 (see Fig. 2 ) a pair of prism wedges 12a with mutually adjustable prism wedges is provided. Following these in the beam path 6 are two independently adjustable plane plates 5 (tiltable around the x-axis and / or the y-axis). The collimated light is transferred at the output 9 to an interface 17, for example, of a microscope 17.1. In the area of ​​a coupling surface 13 located at the output 9 (see Figs. 7 and 8) of the connector housing 8, a coupling structure 14 is present. This interacts with a receiving structure 15 of a connector receptacle 16. In the example, the angle is adjusted to the respective target values ​​via the pair of prism wedges 12a, and the location is adjusted via the pair of plane plates 5.

[0055] The flat plates 5 can be omitted ( Fig. 4 ) when the pair of prism wedges (prism wedge pair 12b) is arranged in a common mount (symbolized by a common frame), which allows the adjusted wedges to be additionally tilted about two axes (x and y) in order to adjust a parallel offset of the beam and to correct a spatial offset. The side surfaces of the jointly mounted prism wedge pair 12b, each facing outwards, away from the other prism wedge, extend orthogonally to the optical axis 3 in an xy plane in the illustrated initial position of the prism wedge pair 12b.

[0056] In a fourth embodiment of the optical plug connection according to the invention, the adjustable optical elements (adjustment means) are arranged in the divergent section of the beam path 6 ( Fig. 5). In contrast to the second and third embodiments, the plane plates 5 are used for angle adjustment and the prism wedge pair 12a is used to adjust the spatial offset with respect to the collimated beam. Due to the increased space requirement and the resulting longer focal length of the collimating optics 2 and the associated larger beam diameter, the requirements for the interface 17 in the microscope change and the space required for the fiber connector 7 increases. In order to enable the longer focal length of the collimating optics 2, a magnifying telescope in the downstream optical system may be omitted. At the same time, the requirements for the positioning accuracy of the collimating optics 2 and the accuracy of the mechanical interface, i.e., the kinematic coupling 19, increase, particularly with regard to the angular requirements to be met.The beam diameter required in the subsequent optical system (microscope) is realized, in whole or in part, at the output of the fiber connector.

[0057] Since the focal length contributes 1:1 to the adjustment sensitivity of the optical lens 2 relative to the fiber ferrule 10, the use of collimating optics 2 with the shortest possible focal length is advantageous for manageable adjustment sensitivity. The corresponding subsequent magnification to the required beam diameter in the downstream optical system of the microscope, for example, using a suitable telescope, also benefits the angular sensitivity of the interface 17 itself. With a typical fiber NA of <= 0.1 in conjunction with approximately 6x subsequent magnification, a good compromise is achieved with collimation to a beam diameter in the range of 0.7 mm. The collimating optics have a focal length between 4 mm and 6 mm, for example.

[0058] In a fifth embodiment of the optical connector, the optical lens 2 is adjustable ( Fig. 6). In the collimated section of the beam path 6, a similarly adjustable plane plate 5 is provided, the latter being designed in the shape of a so-called "window ball." The curved lateral surface facing the observer is symbolized by arcuate lines. An alternative is provided by two plane plates 5 with mutually perpendicular tilt axes (around the x-axis and the y-axis, respectively; not shown).

[0059] To adjust the beam position, lens 2 is adjusted using external adjustment tools (see Fig. 9 ) is positioned in all degrees of freedom on the beam coming from the fiber 1 in such a way that a collimated bundle is formed at the output 9 of the fiber connector 7 opposite the coupling surface 13 (see Figs. 7 and 8) emerges at a precise location and angle. The ferrule 10 can be releasably locked in the fiber bearing 11 by means of a clamping element 20. By adjusting the position of the plane plate 5, the lateral alignment or the centering of the beam path 6 relative to the optical axis 3 is optimized.

[0060] Depending on the wavelength range of the emerging laser radiation, the optical lens 2, which acts as a collimating lens, is designed with simple, chromatic, or achromatic correction. The long-term stability of the transmission of short-wave laser radiation at 405 nm is taken into account in the chromatic and achromatic variants, if necessary, by a correspondingly stable cement layer or a cement-free design.

[0061] The mode of operation of two mutually adjustable prism wedges of a prism wedge pair 12a is shown in the Figures 7a and 7bshown schematically and by way of example. In a first relative position, the prism wedges are rotated by 180° relative to each other in a zero position. In this position, a light beam (arrow) passes along the optical axis 3 or the beam path 6 through the prism wedge pair 12a. The light beam is in the further relative position according to Fig. 7b deflected downwards at a defined angle in the drawing plane.

[0062] In the Fig. 8a A pivoting wedge pair 28 comprising lenses 28.1 and 28.2 is shown. The first lens 28.1 is designed as a plano-concave lens, while the second lens 28.2 is designed as a plano-convex lens. The flat side surfaces of the lenses 28.1 and 28.2 face away from each other, so that the flat side surfaces face outwards and are in the Fig. 8ashown zero position of the pivoting wedge pair 28 extend orthogonally to the optical axis 3 or to the beam path 6. The optical effect of the pivoting wedge pair 28 in the zero position is that a light beam incident perpendicularly, in particular centrally, on a flat side surface passes through the pivoting wedge pair 28 without lateral deflection. In order to largely reduce the effect of the pivoting wedge pair 28 on the collimated beam, the focal lengths of the lenses 28.1 and 28.2 are large and amount to, for example, 1 m.

[0063] The convex and concave side surfaces are coordinated in terms of their dimensions and radii so that they can be moved laterally relative to each other. Fig. 8b The lens 28.2, which has a convex side surface, is shifted laterally relative to the first lens 28.1. The incident light beam is deflected from its original propagation direction.

[0064] The lateral displacement of one or both lenses 28.1, 28.2 of the pivoting wedge pair 28 is effected, for example, by means of a controlled drive (not shown). The associated control commands can be generated by an evaluation unit 25 and implemented by an actuating device 26 (see, for example, Fig. 12 ).

[0065] The pivoting wedge pair 28 can optionally be tilted as a whole around the x-axis and / or the y-axis. The relative position of the lenses 28.1 and 28.2 can be kept constant, for example, creating the optical effect of a plane plate. Optionally, the pivoting wedge pair 29 can be moved along the z-axis.

[0066] A design of the coupling surface 13 of the fiber connector 7 (indicated by a broken solid line) is shown in Fig. 9shown in a top view in the z-direction. The connection of an optical connector according to the invention is achieved by the action of a magnetic coupling 18 and a kinematic coupling 19.

[0067] A ring magnet is provided on the coupling surface 13 or partially or flush with it as a first component 18.1 of the magnetic coupling 18. This ring magnet encloses a passage 23 serving as the output 9 of the fiber connector 7 in a rotationally symmetrical manner. First components 19.1 of the kinematic coupling 19 are provided, offset by 120° from each other. In the exemplary embodiment, these are formed by pairs of parallel and spaced-apart rods. In other possible embodiments, the angles between the first components 19.1 and / or their design can be selected differently.

[0068] A recess 22 enables force-free screwing of the fiber connector 7 as a safeguard against unintentional interruption of the connector connection.

[0069] A receiving structure 15 of the plug receptacle 16, compatible with the coupling structure 14, has three spherically protruding second components 19.2 of the kinematic coupling 19 ( Fig. 10 ). These are compatible with the first components 19.1 of the kinematic coupling 19 in terms of their dimensions and positioning. A second component 18.2 of the magnetic coupling 18 is arranged symmetrically around a passage 23 and has opposite polarity to the first component 18.1 in terms of its magnetization. The second component 18.2 is compatible with the first component 18.1 in terms of its dimensions and positioning. Mounting holes 29 are also shown.

[0070] The connector receptacle 16 has at least one adjustable plane-parallel plate 5 in its beam path 30 ( Fig. 11 ). The adjustment capability of this plate 5 allows the tolerances to be maintained for the beam position of the fiber connector 7 to be wider than is the case with the previous embodiments.

[0071] The method for adjusting a fiber connector 7 is shown schematically in Fig. 12 using a fiber connector 7 according to the fifth embodiment of the optical connector ( Fig. 6). For adjustment, the fiber 1 with the ferrule 10 is inserted into the fiber bearing 11. Light is coupled into the fiber 1 and exits at the end of the fiber 1 located in the fiber connector 7. The fiber connector 7 or its beam path 6 is aligned with an adjustment device 24, which is illuminated with the light exiting the fiber connector 7. The adjustment device 24 can be an autocollimation telescope (ACF), which can be set to two different focus positions and thus combines the functions of both an ACF for angle measurement and an alignment telescope for location determination. For example, the focal length of the ACF can be in the range of 400 mm in order to achieve a high accuracy of less than or equal to one angular second (≤ 1") when measuring angles.

[0072] For the purpose of adjustment, the beam path 6 of the fiber connector 7 is superimposed on the optical axis of the adjustment device 24. The adjustable optical elements, in this embodiment the optical lens 2 and the plane plate 5, are then adjusted such that the light is collimated at the optical output 9 and exits the fiber connector 7 parallel and symmetrical to the beam path 6. The angular and spatial position are measured using the adjustment device 24. In the example of the AKF, this can be done in two measuring processes. The recorded measurement data on the spatial position or angular position can be transmitted to an evaluation unit 25 via a detector 27 connected to the adjustment device 24, for example a CCD camera.

[0073] Required adjustments of the adjustable optical elements, in this embodiment, the optical lens 2 and the plane plate 5, can be displayed, and manual adjustments can then be made. Alternatively, the evaluation unit 25 can be configured such that control commands are generated based on the measurement data and transmitted to one or more adjusting devices 26. The adjustable optical elements are adjusted according to the control commands. This process can be performed iteratively and implemented as a feedback control.

[0074] If the acquired measurement data are within permissible tolerances, the adjustment process is terminated. The adjustable optical elements, and optionally also the ferrule 10, are locked in place, for example, by gluing, potting, soldering, or welding. The ferrule 10 can also be held in its installed position by means of the clamping element 20. This design allows for reuse of the fiber 1 in the event of a defect in the fiber connector 7.

[0075] In a flow diagram of the method according to the invention, the fiber connector 7 and its beam path 6 are aligned relative to an adjusting device 24 ( Fig. 13; Step 0). The adjustment device 24 can have two beam paths with a reference mark for setting an angle in one beam path and a reference mark for setting a location in the other beam path. In the exemplary embodiment of the adjustment method according to the invention explained below, reference is made to an alternative possibility in the form of a FAKF. The FAKF is refocused accordingly for the purpose of adjusting the angle or location.

[0076] The focus of the FAKF or the adjustment device 24 is set to infinity. This corresponds to the functional principle of an autocollimation telescope.

[0077] In step 1 of the method, divergent light emerging from fiber 1 in a beam is aligned as symmetrically as possible to the beam path 6 of the fiber connector 7. The beam path 6 of the fiber connector 7 is aligned to the optical axis of the adjustment device 24 so that the beam path 6 and the optical axis of the adjustment device 24 coincide.

[0078] Subsequently, the optical lens 2 is positioned relative to the beam. By moving the optical lens 2 and / or ferrule 10 relative to each other in the beam direction (z-direction), the beam is collimated by the action of the optical lens 2. The success of the collimation is checked. Step 1 is repeated if the collimation was unsuccessful.

[0079] If collimation is successful, the angle of the beam is adjusted in step 2a by laterally shifting the optical lens 2 relative to the ferrule 10 (see also Fig. 1a). The respective changes in the measured angle can be related to a current change in the position of the optical lens 2, and the adjustment can be made iteratively. As long as a specified target tolerance is not reached, step 2a is repeated.

[0080] If, however, the target tolerance is reached, the focus of the FAKF or the adjustment device 24 is set to finite (escape position).

[0081] Once the angle adjustment has been completed, in a step 2b the optical lens 2 is tilted relative to the ferrule 10 in order to adjust the desired position of the collimated beam (see also Fig. 1b). This location adjustment is comparatively rough. If, in addition to the optical lens 2, a plane plate 5 or a pair of prism wedges 12a, 12b is located in the beam path 6, a fine adjustment of the location can be performed by tilting these. As explained above for the angle adjustment, the location adjustment can also be performed iteratively, i.e., the achievement of a target tolerance is checked. Depending on the result of the test, step 2b is repeated or the user continues with step 2c.

[0082] Step 2c is optional and involves fine-tuning the location. To do this, the plane plate 5, the pair of pivoting wedges 28, or the pair of prism wedges 12a, 12b are tilted.

[0083] To evaluate the results of the previous adjustment steps, the achievement of a predefined target tolerance is again checked. If the target tolerance is not achieved, the adjustment process is repeated, beginning with setting the focus of the FAKF / adjustment device 24 to infinity (autocollimation, between step 0 and step 1).

[0084] Once the target tolerance of the entire adjustment process has been achieved, the process continues with step 3. In step 3, the adjustable optical elements are locked in the adjusted state. The locking can be either releasable or permanent. A fiber connector 7 adjusted in this way can be connected once or repeatedly to different connector receptacles 16. The correct alignment of the light beam provided at the output 9 of the fiber connector 7 and irradiated, for example, into a microscope is maintained. It is advantageous to check the adjustment while the fiber connector 7 is now locked. Reference symbol

[0085] 1 Fiber 2 Optical lens 3 Optical axis (of the optical lens) 4 Prism wedge 5 Planar plate 6 Beam path (of fiber connector 7) 7 Fiber connector 8 Connector housing 9 Output (beam path 6) 10 Ferrule 11 Fiber bearing 12a Pair of prism wedges 12b Pair of prism wedges in a common mount 13 Coupling surface 14 Coupling structure 15 Mounting structure 16 Connector receptacle 17 Interface 17.1 Microscope 18 Magnetic coupling 18.1 First component 18.2 Second component 19 Kinematic coupling 19.1 First component 19.2 Second component 20 Clamping element 21 Permanent locking device 22 Recess (for force-free screw connection) 23 Passage 24 Adjustment device 25 Evaluation unit 26 Adjustment device 27Detector 28Pair of pivoting wedges 28.1First lens 28.2Second lens 29Mounting holes 30Beam path (of the connector receptacle 16)

Claims

1. Fibre plug (7) for the optical coupling of a light-guiding fibre (1) with a plug receptacle (16), comprising - a plug housing (8) for receiving and locking component parts of the fibre plug (7) in a predetermined position relative to one another; wherein the plug housing (8) has - a fibre inlet and a fibre bearing (11) for the spatially fixed reception of the light-guiding fibre (1); - optically downstream of the fibre bearing (11) along a beam path (6), at least one optical lens (2) for collecting light exiting at an end face of the light-guiding fibre (1) and for collimating the collected light; and - a coupling surface (13) with an output (9) of the beam path (6) and with a coupling structure (14) for connection to a receptacle structure (15) of the plug receptacle (16), said receptacle structure being complementary to the coupling structure (14), wherein - besides the at least one optical lens (2) at least one adjustable optical element is arranged optically downstream of the fibre bearing (11) in the beam path (6); and - the coupling structure (14) has a first component (18.1) of a magnetic coupling (18) consisting of two components and a first component (19.1) of a kinematic coupling (19).

2. Fibre plug (7) according to Claim 1, characterized in that a prism wedge pair (12b) with two mutually adjustable prism wedges is arranged in a common mount as the adjustable optical element and the jointly held prism wedge pair (12b) is tiltable about a plurality of axes.

3. Fibre plug (7) according to Claim 1, characterized in that a pivot wedge pair (28) is provided as the adjustable optical element, which comprises two lenses (28.1, 28.2) whose side surfaces facing away from one another are designed as planar surfaces and wherein the lenses (28.1, 28.2) can be inclined relative to one another and / or displaced laterally.

4. Fibre plug (7) according to Claim 1, 2 or 3, characterized in that the optical lens (2), the lenses (28.1, 28.2) of the pivot wedge pair (28) or existing prism wedges of the prism wedge pair (12b) are corrected achromatically to the spectral range or wavelength range intended for use.

5. Fibre plug (7) according to Claim 1, characterized in that at least one plane-parallel plate (5) is arranged as the adjustable optical element.

6. Fibre plug (7) according to Claim 5, characterized in that a further plane-parallel plate (5) and / or a pair of mutually adjustable prism wedges (12a) is or are arranged in the beam path (6).

7. Fibre plug (7) according to one of the preceding claims, characterized in that a light-guiding fibre (1) is retained in the fibre bearing (11), wherein a light exit surface of the fibre (1) is directed along the beam path (6).

8. Fibre plug (7) according to one of the preceding claims, characterized in that a clamping element (20), by means of which a fibre (1) received in the fibre bearing (11) can be or is retained, is present in the fibre bearing (11).

9. Fibre plug (7) according to Claim 7 or 8, characterized in that the adjustable optical elements are adjusted such that light exiting the fibre (1) is provided or can be provided at the output (9) of the fibre plug (7) parallel and symmetrically with respect to the beam path (6); and the adjustable optical elements are locked in the state adjusted in this way.

10. Optical plug connection comprising a fibre plug (7) according to one of Claims 1 to 9 and a plug receptacle (16), wherein the plug receptacle (16) has - a second component (19.2) of the kinematic coupling (19), which is designed to be complementary to the first component (19.1) - situated on the fibre plug (7) - of the kinematic coupling (19), as a receptacle structure (15); and - a second component (18.2) of the magnetic coupling (18) consisting of two components.

11. Method for adjusting a fibre plug (7) according to one of Claims 7 and 8, comprising the steps of - aligning the fibre plug (7) and its beam path (6) relative to an adjustment apparatus (24); - illuminating the adjustment apparatus (24) with light from the fibre plug (7) and adjusting the adjustable optical elements until light exiting the fibre (1) is provided at the output (9) parallel and symmetrically with respect to the beam path (6); and - locking the adjustable optical elements in the state adjusted in this way.