DE2926003A1 - DEVICE AND METHOD FOR PRODUCING PARTS OF AN OPTICAL BRANCHING ELEMENT - Google Patents

Description

2326Q03

SIEMENS AKTIENGESELLSCHAFT Our symbol Berlin and Munich YPA 79 ρ 7 O 8 3 BRD

Apparatus and method for manufacturing parts of an optical branching element.

The invention relates to a device for manufacturing of parts of an optical branching element working according to the beam splitter principle, these parts at least contain an optical waveguide which at least forms an angle v © n with the normal to a side surface includes approximately 45 °. The invention also relates to an adapted manufacturing method.

Optical branching elements based on the beam splitter principle are, for example, from the IKKFi catalog No. 79, CH 1431-6 QEA, 1979, pages 80, 82 and 83. In a precisely shaped, right-angled and isosceles part there is a fiber optic cable included as the bisector of the right angle. The two enclosing the right angle Side surfaces are then enclosed with the. 20 polished fiber optic cables. Through precise joining several such parts with the interposition of a partially transparent mirror, for example

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a thin metal layer or a dielectric Mirror, a branching element is formed. The grinding of the optical facets in the tips of these individual parts causes considerable difficulties. The tips of the fiber optic cables can be cut when grinding break off easily so that these parts can no longer be used for a low-loss transition.

Other optical branch elements based on the beam splitter principle have also been proposed in which first of all butt against another optical fiber to a continuous optical fiber. The fiber optics are in guide grooves, for example one Silicon wafer or another substrate, guided and fixed with a cover by putty. This "sandwich" is then turned at 45 ° to the Optical waveguides severed in the creation point of these optical waveguides. Then the parting surfaces optically polished flat, a separating surface mirrored and the two parts put back together exactly and cemented. Breaking out of the optical fiber ends during grinding is excluded, so that optical branching elements with very low transmission losses can be produced with a high yield.

The present invention is based on the object to further reduce the manufacturing costs, in particular an automatic production of these branching elements or to enable parts of these economically in large numbers.

According to the invention, this object is achieved by a molded body with at least one precision recess for receiving a casting compound and a guide groove for each

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seen fiber optic cable solved. The molded body can only have a precision cutout, the shape of which corresponds to the desired part of the branching element is equivalent to. In particular for the production of large numbers, however, it is also advantageously possible to use in to provide two or more precision cut-outs for the molded body at the same time and to arrange them, for example, that at least one optical waveguide can be provided jointly for all precision cutouts.

For making one half of the optical branching element with two mutually perpendicular optical waveguides is a further development of the invention provided that the axes of the two guide grooves on the edge of the precision recess with which they each Include an angle of 45 °, cut. The optical fibers are then inserted one after the other in such a way that that the end of the second is butt against the first. Around the intersection of these two To be able to correct optical waveguides even after they have been inserted, a guide groove is designed conically in the part facing away from the precision recess. Additionally a separate adjusting part is provided with a guide groove outside the molded body. With help this adjustment part is the exact adjustment of the optical waveguide lying in the conical guide groove possible at the joint with the continuous fiber optic cable. This adjustment is unique executed. The adjustment part is then rigidly connected to the molded body. The parts you want can can be produced by filling the precision cutouts with a potting compound after inserting the optical waveguide into the guide grooves. Included all you have to do is ensure that the optical waveguides are immovable during this process.

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For a defined surface of the part to be manufactured it is advantageous that the molded body can be closed with a cover. This cover then ensures at the same time for the fixation of the fiber optic cables. In the simplest case, it can be a flat cover act or a lid that is a copy of the molded body.

For problem-free removal of the finished parts from the mold, it is provided that the precision cut-outs Has ejection ram.

As already stated, the finished parts must have at least one surface with the enclosed optical waveguide be optically polished flat. To facilitate the necessary grinding process and the exact angular position To be able to maintain within narrow tolerances, it is provided that the shaped body along the edge the precision recess that the axes of the guide

cuts grooves under 45 °, has one or more depressions. In particular, it is provided that a this trough lies in the area of the intersection of the axes of the guide grooves and the edge. These hollows can be designed in the form of a quarter ball, so that when potting with a lid, which is, for example, a copy of the molded body, wart-shaped There are bumps on the surface to be sanded. When grinding, only these Elevations are polished off. Furthermore, the trough can be in the area of the coupling point of two optical waveguides be used so that initially only the trough is potted with a hardening adhesive and thus the Optical fibers are fixed in their position to one another in the area of their coupling point. In the molded body for example, an additional dosing entry

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79 P 7 O 8 3 BRO direction to be provided. An optical adhesive that cures quickly when exposed to UV light is recommended as particularly suitable. When using a cover, a part of the cover must be suitable for illumination with UV light. After the optical cement has hardened, the entire precision recess is then filled with a potting compound. It is important that the potting compound is intimately bonded to the surface of the optical waveguide and to the optical adhesive in the cavity. In the event that the optical waveguides butt against each other in the area of the coupling point, the potting compound must be optically transparent at least in this area so that the light is not lost in the interstices between the optical waveguides when coupling from one optical waveguide to the other.

In an advantageous further development of the invention it is provided that shaped pins are inserted into the precision recess protrude whose axes are aligned with the axes of the guide grooves. Result in the finished cast parts as a result, there are cylindrical depressions on the outer surfaces in the area of the optical waveguides, in which, for example Glass capillaries can be used. A finished branching element equipped in this way can be incorporated into a Housing are installed, which has a number of holes corresponding to the number of optical fibers and - As already proposed - is provided with connectors, which with respect to the axes of the optical waveguide on Housing adjusted and then fixed. The function of the glass capillaries is to control the pressure of the later to be coupled mating connector and to distribute it over a larger area of the potting compound, so the sensitive end faces of the optical waveguides of the 'branching element are not damaged.

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Further advantages of the device according to the invention and of the method for producing parts of a branching element are given in the exemplary embodiments, which are described in more detail below with reference to seven figures and explained.

Fig.1 shows a possible design of the lower Part of a "device for producing one half of a branching element. 10

Fig.1a shows an enlarged section through both parts of the device in the area of a shaped pin.

Fig.2 shows the further processing of an ejected Half of a branching element.

3 shows one made from two such halves Branching element.

FIG. 4 shows one with the same device according to FIG manufacturable other embodiment of an element half.

Fig.5 show two variants of a complete branch ¹ ^ ² element with housing and connectors.

FIG. 7 shows a plan view corresponding to FIG

the lower half of a device for simultaneous Manufacture of both element halves. 30th

1 shows a plan view of the lower part 1 of the molded body of a device for producing a half of a branching element with a precision cutout 2. At the bottom of this cutout there is a ejector punch, not shown here, with a plane

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Stamp surface parallel to the plane of the drawing. The guide grooves 4 and 6 serve to accommodate the optical waveguides 9 or 10. In the area of the point of intersection of these optical waveguides there is one in the molded body small depression 5 in the form of a quarter ball, so that when pouring with the upper part of the molded body attached a wart-shaped elevation along the edge A- · is created. Two further depressions of this type are indicated by dash-dotted lines, which increase the angular accuracy during grinding still increase.

In order to form circular cylindrical depressions in the cast parts in the area of the optical waveguides 9 and 10, molded pins 3a and 3b are provided in the molded body. 1a shows a section through the lower part 1 of the shaped body and the upper part I of the shaped body in the area of a shaped pin, the halves being shown moved apart by a small distance δ. As can be seen from this figure, the two shaped pin halves 3b and HIb have guide grooves 4 and 4 ^1, respectively, for receiving the optical waveguide 9. When casting the halves of the branch element, the two parts of the molded body are pressed together so that the distance S = zero.

As can also be seen in FIG. 1, the guide nut 6 is designed conically away from the precision recess 2 in order to enable precise adjustment of the optical waveguide 10 at the coupling point with the continuous optical waveguide 9 by means of a part 7 with a guide groove 8. This adjustment is carried out once on the casting device. This adjustment is used to ensure that the intersection of the axes of the optical waveguides 9 and 10 lies exactly in the center of the trough 5, ie on the edge A ^f .

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One element half is now produced in such a way that the optical waveguide 9 is first inserted into the guide groove 4 of the lower part 1 of the molded body is inserted. The optical waveguide 9 must be in the area of the molded body, but at least in the area of the trough 5, it must be free of any plastic coating. To the fiber optic cable 9 the optical waveguide 10 is brought up. The end face of the optical waveguide 10 must be flat and be free τοη interference. Then 'becomes the upper one Part I of the molded body is firmly connected to the lower part 1 and the precision recess 2 to the potting compound poured out. After hardening, the element half can be ejected. As a casting compound is advantageous an optically transparent material is used. The casting compound should also harden quickly.

However, it is also conceivable that before the precision recess 2 is completely poured out, the optical waveguides 9 and initially only be glued to an optical compound in the area of the trough. For this purpose, there is one in the molded body additional metering device to be provided. An optical adhesive can be particularly suitable, which quickly UV exposure cures. When using such an adhesive, a UY lamp must illuminate the area of the well 5 can, which is made possible, for example, by the fact that the upper part I of the molded body has a removable lid. After the optical adhesive has cured, the entire precision recess 2 is then covered with a casting compound filled. It is important that the casting compound is intimately connected to the surface of the optical waveguide and the optical Glue connects.

In Figure 2a, the ejected half 111 of the branch element is which consists of the cast part 11 with the optical waveguides 9 and 10. Through the two

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The circular cylindrical depressions formed by the cones 3a and 3b are already fitted over the optical waveguides with glass capillaries 12a and 12b, which have to be cemented to the optical waveguides and the cast part 11. The element half 111 is now polished flat on the three outer surfaces Fg, Fg ¹ and F ^ ₀ perpendicular to the plane spanned by the optical waveguide, so that optical surfaces are created in the area of the glass capillaries 12a and 12b and at the optical coupling point of the optical waveguides 9 and 10. Since only the nipple 13 has to be polished off in the area of the coupling point, the base area Fq ¹ , which is large for polishing, ensures that the critical surface position (intersection of the fiber axes exactly in the 45 ° end face Fg ') can be maintained within narrow tolerances. The polished element half is shown in Fig.2b. 2c shows an enlarged section around the coupling point.

The end face Fg ¹ is now provided in a known manner with a beam splitter mirror 15 and then optically cemented with a non-mirrored but otherwise identical element half 112 as shown in FIG. 3 to form a branching element 110. It is important to ensure that the axes of all four optical fiber sections are exactly aligned. Assembly is made much easier if the surfaces Fg and F..Q are used as reference surfaces and the two element halves 111 and 112 are joined on a flat mounting plate with stop edges.

Another embodiment of a corresponding to FIG. 2a Figure 4 shows the element half. The same parts are again provided with the same reference numerals. In this case are instead of the glass capillaries fiber optic cable armouring 14a and 14b over the exposed ends of the ' Optical fiber slipped over and connected to the cast part 11

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putties. The polishing of the 45 ° end face P _g »is carried out as before. Two element halves are then cemented again, one of which is mirrored, analogous to the exemplary embodiment according to FIG. This cemented branching element can finally be cast externally to increase the mechanical strength of the cemented surface and to protect it, so that only the four cable ends are exposed.

In Fig.5 it is shown how a branching element 110 according to FIG. 3 is installed in a housing 16 which has four bores 17a to 17d. In the area of these bores, flanges 18a are placed on the outside of the housing to 18d adjusted in relation to the axes of the optical waveguides and then fixed. Thanks to precision bores in these flanges, external light can later be used Waveguide connector coupled with its end faces directly to the end faces of the branching element 110 will. The glass capillaries 12a to 12d have the function of absorbing and releasing the pressure of these plugs to distribute a larger area of the potting compound, so that the sensitive end faces of the optical waveguide of the Branching element are not damaged.

6 shows another embodiment with a branch element 110 ¹ , in which longer glass capillaries 12a ¹ to 12d 'are cemented into the depressions in the potting parts. As a result, threaded flanges can be placed directly on these glass capillaries and rigidly connected to ^{the branching element 110 f, for example by an extrusion coating 21.} Precision sleeves 20a to 20d that are centered with respect to the axes of the optical waveguides are placed on the threaded flanges. The plugs formed in this way can be connected to external mating plugs in the usual way.

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Fig. 7 shows a device for the simultaneous production of both element halves. The same parts are again provided with the same reference numerals as in FIG. The reference numerals for the parts of the second element half are marked with an additional line. In this embodiment of the potting device, the trough 5 according to the embodiment according to FIG. ^{1 is replaced by a gap between the two webs 5a 1} and 5b 1. Here, too, it is advantageous to produce only a circular cylindrical pin instead of the former wart as a connection between the two "blanks". All other process steps for generating a branching element correspond to those described above.

7 figures

12 claims

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Claims (12)

79 P 7 O 8 3 BRO Patent claims: Gate direction for the production of parts of an optical, according to the beam splitter principle working ter-branch element, these parts having at least one optical waveguide contain, which at least includes an angle of approximately 45 ° with the normal of a side surface, characterized by a shaped body with at least one precision recess (2) for receiving a potting compound and a guide groove (4,6) for each intended optical waveguide (9,10). 2. Device according to claim 1 with two guide grooves per precision recess, characterized in that that the axes of these two grooves (4,6) on the edge (Aq ') of the precision recess (2), with the they each enclose an angle of 45 °, cut. 3. Door direction according to claim 2, characterized in that a guide groove (6) in that of the precision recess (2) facing away from the part is conical and that an additional adjustment part (7) with a guide groove (8) is seen in the gate. 4. Device according to one of claims 1 to 3, characterized in that the shaped body with can be closed with a lid. 5. gate direction according to claim 4, characterized that the lid is a copy of the molded body. 6. Gate direction according to one of claims 1 to 5, characterized characterized that the precision 030063/0274 ORIGINAL INSPECTED 232SQ03 " ² ~ 79 ρ 7 O 8 3 BRO recess (2) has an ejector punch. 7. Device according to one of claims 1 to 6, characterized in that the shaped body along the edge (Aq ¹ ) of the precision recess (2) which intersects the axes of the guide grooves (4, 6) at 45 °, one or more depressions ( 5). 8. Apparatus according to claim 7, characterized in that a trough (5) lies in the region of the intersection of the axes of the guide grooves (4, 6) and the edge (Aq ^1). 9. Device according to one of claims 1 to 8, characterized in that in the precision recess (2) Shaped pins (3a, 3b) protrude, the axes of which are aligned with the axes of the guide grooves (4, 6). 10. Device according to one of claims 1 to 9, characterized in that the potting compound is optically transparent. 11. Device according to claims 7 and 10, characterized in that the potting compound in the area the trough (5) is optically transparent. 12. Process for the production of a part of a branching element with a device according to one of claims 1 to 11, characterized in that that optical waveguides (9, 10) are inserted into the guide grooves (4, 6) of the molded body and, if necessary, adjusted to one another that the precision recess (2) is filled with a potting compound and that after hardening of this mass the surfaces whose normals are the 030063 / 027A 79 P 7 0 8 3 FRG Cut the optical waveguides (9, 10) at 45 ° and polish them optically. 030063/0274