Method of manufacturing connectors for optical waveguides.

The present invention relates to a process for the preparation of optical waveguide couplers, in particular for glass fiber optical waveguide.

In optical communications transmission systems-play components, such as an output coupler, which defined light components from system-optical waveguides on and can be coupled, an important role. In addition to the physical properties of the structures in regard to the production of large series, the simplicity of the manufacturing technology of crucial importance. This demand is not been solved satisfactorily in almost all today unrealized branch couplers.

Object of the present invention is to provide a method of the aforementioned type, which is advantageous for producing Lichtwellenleiterkop^p- learning how tap coupler or plug connections in series is.

The object is achieved by the measures indicated in the characterizing part of claim 1.

Advantageous processes penetrations and a method for producing a parallel light conductor structure will become apparent from the subclaims.

An exemplary method is illustrated by the figures in the following description, from which arise the advantages of the process. The figures show<ul><li>1 shows, in perspective view of a drum on the jacket, a glass fiber light waveguide is wound in one ply into a cylindrical coil, is adhered to the one crosswise to the individual turns of the coil extending adhesive strips</li><li>Fig.2 in perspective a recovered from the solenoid parallel optical waveguide structure,</li><li>3 shows in the same text display two output disconnecting parts caused by completely severing the parallel optical waveguide structure according to Figure 3 transverse to the longitudinal direction of the glass fibers,</li><li>4 shows in the same representation, but enlarged, two separate members, which are formed by separating the two output partition members,</li><li>5 shows in plan view the bearing surface of a guide body, the two laterally offset, has parallel guide surfaces, which are perpendicular to the bearing surface, and the two separate members to Fig.4 that up with mutually facing separating faces on the bearing surface and laterally on the guide surfaces bear, and</li><li>6 shows in perspective view a plug portion of a plug connection.</li></ul>

It should be noted that the drawings are not to scale.

In the process example, a freshly drawn, dünnmantelige core-sheath fiber is wound in one layer on the periphery of a capstan Z, so that it forms a cylindrical coil W. Right across the individual windings a tape K is set so that adhere to the fibers of the individual windings thereon. Then the coil W is separated at a distance from the adhesive strip. There were thus obtained in the simplest manner a wide range of already in a plane parallel juxtaposed light guides.

In a typical example, a glass fiber was of 200_/wrapped around a drum diameter of 10 cm diameter and 20 cm length, which parallel juxtaposed fibers corresponds to about 1000, provided that they touch each other. Instead of one adhesive strip can also more distributed over the circumference of adhesive tape are glued to the cylindrical coil or two. It can be prepared with a variety of parallel juxtaposed fibers then twice or more severing the fiber several such structures. The length of the parallel juxtaposed fibers or their number may be varied by the drum diameter and the coil or drum length within broad limits.

The parallel to each adhering to a tape of glass fibers will now be placed on a surface of a sufficiently long glass strip 1 (Fig.2) so as to extend transversely to the longitudinal direction of the strip and attached to a, at an end side of the glass strip 1 on the surface of the stop ₁1 bear. For the above mentioned specific example, a glass strip by 21 cm in length, 5 mm in width and 4 mm nöhe was used.

The thus coated fibers are * on the Glasstrei - fen 1 by two narrower strip of glass 21 and 22 is covered, extending over all the fibers. The two narrower strip of glass 21 and 22 are parallel arranged adjacent to the bar and at a distance from each other so that between them a gap-shaped opening 23, which extends across all of the fibers remains. In the specific example, the narrower strips had a width of 1.5 mm, while the length and height of the glass strip 1 which corresponded. The width of the slit 23 was 2 mm.

The cover 2 formed by the two narrower strips 21 and 22 is one end on the stop 11 in which, while the other end face rests on an intermediate plate 3, which is inserted between the glass strip 1 and cover the second The cover 2 is now burdened with some Gramm'Gewicht and thus secured against displacement and the adjacent fibers, which are denoted by 201-233 are pressed by means of the intermediate plate 3 against the stop 11, thereby ensuring that they touch each other. The distance of the cover 2 from the surface of the glass strip 1 should in this case be not greater than twice the diameter of a glass fiber. In the specific example, the thickness of the stopper 11 and the intermediate plate 3300 was_/Thus, in order, was slightly larger than the diameter of a fiber.

To fix the glass fibers 201-233 23 adhesive is introduced into the gap, which is expediently carried out prior to compression of the fibers, so that the adhesive can penetrate to the surface of the glass strip. 1 After curing of the adhesive that shown in Fig.2 parallel light conductor structure 1 is formed, in which the glass strip 1, which forms the carrier body, the optical fibers 201-233, which are in contact, and the cover 2 are firmly connected together.

As the adhesive, for example, is a two-component adhesive of the company. Ciba-Geigy, the glue with V.P + W396 and the hardener with V.P + is called W397. In the particular example, this adhesive was used with a mixing ratio of ten parts of adhesive and three parts hardener.

The parallel light conductor structure 1 is now completely severed by a guided in the gap 23 along the narrower strip of glass 21 and 22 are cut, so that two output isolation halves 1 'and 1 "to arise as they are shown in Fig.3. The sectional are of the cured adhesive, all fibers 201-233, the intermediate plate 3, the stop 11 and the glass strip 1 has been severed. Each output separator 1 'and 1ⁿ thus consists of a glass strip 1, or

1 ", on the parallel juxtaposed and touching optical waveguide 201 'to 233' or 201" to 233 "means hardened adhesive 4 'or 4", a stop 11' and 11 ', an intermediate plate 3' and 3 " and a narrower strip of glass 22 and 21 is fixed. Each of the two output disconnecting parts 1 ', 1 "has a formed by cutting parting surface, of which in Figure 3, only the separating surface 5' of the starting partition member 1" can be seen. As these divisions include the faces of the severed fiber, such divisions are referred to as separation faces.

The parting faces of both output disconnecting parts 1 'and 1 "are now processed and brought to polish. Depending on the quality of the separation face, which is caused by the severing, is the processing in a grinding process with subsequent polishing process or a polishing process alone. The cutting is advantageously carried out by cutting, sawing, or by milling. In the particular example was sawed, sanded and polished.

In the production-by branch couplers with identical coupling ratio so doing that the two output partition members' will and 1 "so interconnected with polished separating faces that the parting faces facing each other and parallel, and the glass fibers 201 1 'to 233' and 201 "to 233" laterally offset, that is defined in the longitudinal direction of the glass strip 1 'or 1 ". Of the output coupler thus manufactured, in which all the fibers are offset in the same way against each other, smaller tap coupler will now be separated with a desired number of glass fibers. It can, as was the case with the specially len example, tap coupler are separated by less than 2 mm in width.

In the production of a variety of branching couplers having different branching ratios so doing, that "with polished separating faces smaller partition members are separated from the output partition members 1 'and 1, which are called partition members. With respect to Figure 3 For example, assume that to dash line I, which is substantially parallel to the light conductors, but this is not necessary, already separating portions have been separated. By severing along the dashed line II, which runs here in parallel with the line I, a further two partition members are now created that are shown enlarged in Figure 4 and designated by 6 'and 6 ". The separating Abtrennteilen may be made by others in principle at each output partition member independently. However, it is advisable to prepare partition members as it is indicated in Figure 3. The optical waveguide of such partition members are formed by cutting through the same optical fiber. Two separating portions, preferably two separating portions 6 'and 6 "are joined so tightly that their parting faces facing each other and parallel and the optical fibers are laterally offset from each other. For each coupler so produced the offset can be individually and thus also the coupling ratio can be adjusted.

Two to connecting separate members, ie, output disconnecting parts and separating portions, are expediently connected to one another by means of a guide body. For example, assume that the two partition members ' "are connected to each other. For this purpose, the two partition members 6 are and 6' and 6" 6 on a flat support surface 61 of the guide member 6 down. The support surface 61 is bounded by a in a direction R rectilinear guide edge 62nd The two partition members 6¹ and 6 'are placed on the support surface 61, that of the glass strip 1' or 1 "resulting strip portions 10 'and 10 lie" on the supporting surface. This ensures that the fibers 219' to 224 'and 219 "to 224" of the two partition members have the same distance from the flat support surface 61st

The leading edge 62 is composed of two in the direction R rectilinear guide member edges 621 and 622 that are perpendicular to this direction a distance ε from each other and in the direction seamlessly into one another.

The two separating portions 6 'and 6 "are arranged on the support surface 61 so that their parting faces 50' and 50 'face each other and with their side surfaces 611 _bbetw. 61 "abut the FUhrungsteilkanten 621 and 622, respectively.

Both separating portions 6 'and 6 "are now pressed against the leading edge 62 and matched by moving in the direction R, so that the polished separating faces 50' and 50" touch or what is recommended, except for a thin intermediate adhesive layer, the previously was applied, have approached. The adhesive used for this example, is suitable Sylgat 182^(R) Fa. Corning.

This final state is shown in Fig.5. The optical waveguides 219 'to 224' of Abtrennteiles 6 'are compared to the optical waveguides 219 "to 224" of Abtrennteiles 6 "ε staggered laterally by the distance.

The voltages on the FUhrungsteilkanten 621 or 622 side faces 61 'and 61 "must be flat and smooth enough to obtain a sufficiently well-defined offset and extend at the same angle to the optical fibers. It is sufficient if these side surfaces are ground or polished.

A lateral displacement can also be generated when one or more resilient guide edges are used by different pressures to be connected partition members, such as the partition members are ', applied to the leading edges 6 and 6 vertically. Resilient guiding edges can be made of elastic material, but it can also be movable, via spring loaded guide edges.

A further possibility is that a layer of elastic material is applied on a side surface of at least one separating member, for example a Mylart^(R)Foil, which is applied to the leading edge. Again, an offset by the application of pressure or different pressures can be set.

For elastic materials can be depending on the elasticity of the material by printing an offset or offset in addition to 20_/to produce.

To connect two matched partitioning parts, as shown in Figure 5, advantageously a tile is glued, so that the two separate members are already fixed.

In the production of plug connections so doing, that are attached before editing the parting faces to form profile strips elements two or more separating members each in a U-shaped rod, so that the optical fibers are parallel to the longitudinal axis of the rod.

First, then, such a profile rod element is mounted parallel to a further U-profile rods. This additional profile rods and an additional such further U-profile rods are laterally applied to a rectilinear guide edge on a support surface of a guide body so that the parting face of the on the other profile rods fasten th partition member facing the additional extended profile rods. is on this additional additional profile rods or is registered chopsticks element was placed with a separator so that the parting face of his separation member of the other separation end face opposite and abutting side faces of another and still another profile rod on the guide surface.

Now, the added profile rod element is adjusted to the fixed profile rod element so that light guides of the two elements are aligned. Then the einjustierte profile rod element is fixed on the additional extended profile rods and only then brought separating faces of each have two profile rods fi ed partition members including the profile rods to polish that plug parts have arisen.

Such a ready-made connector part is shown in Fig.6. This plug part consists of the chop in part 6 "of Figure 4, which is secured by means of adhesive 64 at the U-profile strips 65 and together with the profile rod element 60 forms. This profile rod element 60 in turn is mounted in the other U-shaped rods 67 by means of adhesive 66 . the smooth side surface on the other profile rod that is used to create a guide surface is denoted by 68. for bondings same adhesive as used for fixing the optical fiber on the glass strip 1 in Figure 2 is suitable. for the profile rods preferably metal rods used.

In the series production of plug parts so doing, that each produced plug part is compared with the same prototype, as for example, which can serve the finished plug part according to Figure 6, adjusted.

To produce the plug connection the mated connector parts are placed onto the support surface of the guide body and pressed by means of screws to these and to the guide surface and thus fixes. The axial distance can be up to a few_/be adhered to light. A common cap may protect against dirt and mechanical damage. As currently glass flakes by milling with a thickness variation of less than 3_/order can be readily prepared, the consequent plug loss when connecting any connector parts are less than 0.5 dB. The adjustment of the connector parts, just as at the branch couplers very simple if the connector output power is measured, whereupon yet been received. When the two connector halves no material abrasion occurs, so that from then forth not increase the connector losses over time.

By fine-tuning of produced plug parts on the same prototypes ensures that the plug parts are interchangeable.

Conveniently, the coupling ratio of the tap coupler as well as the plug connections in a measuring site is monitored. Here, a light guide from one of the two matched partition members or connector parts is excited by a light wave corresponding to the stationary mode spectrum of the light guide as close as possible. The output of one or the output power ratio of two leading away from these optical fibers optical fibers of the other partition member is continuously measured. The_Ausgangslei- performance or use the _Ausgangsleistungsverhältnis constantly, for example, a computer monitor, while the partition members of each branch coupler or connector halves of each connector connecting eg be moved by a stepper motor. When the predetermined output power or the predetermined power ratio is exeicht, the additional propulsion is stopped and fixed the two partition members and the connector parts.

It should finally be noted that a method described above not only identical tap coupler of less than 2 mm in width, but also correspondingly narrow tap coupler variable coupling ratios and narrow plug parts can be produced because also separating portions of less than severable 2 mm width.