EP1412793A1 - Optical coupling unit and method for inserting optical wave guides into an optical coupling unit - Google Patents

Abstract

The invention relates to a coupling unit (1) for optically coupling a multi-channel optical plug-in element (8) to at least one opto-electronic converter (11) of a multi-channel transmitter and/or receiver unit (10) and to a method for inserting optical wave guides (71) into said optical coupling unit (1). The coupling unit (1) comprises a first coupling side (1e) for optical coupling to the multi-channel optical plug-in element (8), a second coupling side (1f) for optical coupling to the at least one opto-electronic converter (11) and a plurality of receiving openings (2) for optical wave guides (17); said openings being arranged on a plane, extending from the first coupling side (1e) to the second coupling side (1f). According to the invention, the coupling unit (1) is embodied in a single piece and the receiving openings (2) extend at least partially inside the coupling unit (1). The optical wave guides (71) are inserted into the single-piece coupling unit (1) with the aid of an optical plug-in element (8). The receiving openings (85) of the optical plug-in element (8) are flush with the receiving elements (2) of the coupling unit (1).

Description

description

Description of the invention: Optical coupling unit and method for threading optical fibers into an optical coupling unit.

The invention relates to a coupling unit for optically coupling a multichannel optical plug-in element with at least one opto-electronic converter of a multichannel transmitting and / or receiving unit and a method for threading optical fibers into such a coupling unit.

For coupling and connecting an optical plug element, in particular an optical plug with light-emitting or light-receiving opto-electronic converters, it is known to provide a separate optical coupling unit. The high-frequency optical signals to be transmitted are conducted and guided in the opposite direction via the optical coupling unit from the optical connector to the opto-electronic converters.

Conventional coupling units of this type consist of a two-part carrier part, in which optical fibers (glass fibers) arranged in one plane are held in V-shaped grooves in one part. The optical fibers are pressed into the grooves by an additional slide, which is provided by the other part. The end faces are then polished and guide pins installed.

The known coupling unit has the disadvantage that the adjustment and fixation of the glass fibers by means of a slider can only be achieved by the highest accuracy of all dimensions, which involves a lot of effort and a high level of rejects. There are also acceptable positional tolerances between the V-shaped grooves for the optical fibers and holes for guide pins that are laterally on the V-shaped Grooves are arranged, difficult to reach. There are high injection mold costs due to complex measurements, tests and adjustments.

Another disadvantage is that relatively expensive pins with a ring boss are required as guide pins, which are introduced into bores for the guide pins with a shape undercut. Overall, there is thus a relatively complicated assembly of the known coupling unit, which requires a high level of assembly effort.

Proceeding from this prior art, the present invention has for its object to provide an optical coupling unit and a method for threading optical fibers into such an optical coupling unit, which ^' in a simple manner the manufacture of the coupling unit and the threading of optical fibers into the Enable coupling unit.

This object is achieved according to the invention by a coupling unit with the features of claim 1 and a method with the features of claim 12. Preferred and advantageous embodiments of the invention are specified in the subclaims.

Thereafter, it is provided that the coupling unit is formed in one piece, the receiving openings for optical waveguides to be inserted into the coupling unit running at least partially in the interior of the coupling unit. According to the invention, only a single part is therefore used as the coupling unit. In this part, both the receiving openings for the optical waveguides and longitudinal bores for receiving and positioning guide pins are formed, with which the coupling unit can be aligned with other elements, in particular an optical connector. The manufacture of the coupling unit as a part eliminates all the problems associated with the use of a slide for introducing the optical waveguides in the prior art. In particular, no force-controlled assembly is required and does not exist

Problem of an uneven pressure of the optical fibers. To introduce the optical fibers, they are instead threaded into the corresponding receiving openings in the coupling unit, as described below. There is also advantageously a reduced number of parts, so that no two injection molds are required to manufacture the coupling unit.

Another advantage of the solution according to the invention is that the receiving openings for the optical waveguides are surrounded on all sides by the same material thicknesses, so that there is a compact, closed and protected arrangement.

In a preferred embodiment of the invention, the coupling unit has on its upper or lower side a preferably centrally arranged recess which partially exposes the receiving openings for the optical waveguides. Via the recess, it is possible to insert an adhesive into the coupling unit for gluing the optical fibers in the receiving openings.

In a preferred development, the coupling unit is associated with an auxiliary auxiliary steeply with a knob protruding from an essentially flat surface. The coupling unit can be arranged on the auxiliary part in such a way that the knobs protrude into the recess of the coupling unit and adjoin the openings for receiving the optical waveguides. The additional auxiliary steep serves as a threading aid and holds when threading

Optical fibers guide them down in the area of the recess. The coupling unit preferably has means for receiving and latching guide pins (also referred to as guide pins or centering pins). These are advantageously two longitudinal bores, which each run to the side of the receiving openings for the optical waveguides and have a constriction, each of which serves to lock a guide pin. The associated guide pin is preferably provided with an annular groove, which snaps into the constriction of the longitudinal bore.

The use of guide pins with an annular groove has the advantage of a simpler and more cost-effective production process compared to the previous use of guide pins with thickenings. The guide pins are preferred with centerless ones

Cylindrical grinding machines manufactured, the guide pin is moved axially between two counter-rotating discs. This method also has the advantage that guide pins with low surface roughness can be produced. A smooth surface of the guide pins advantageously reduces wear on the coupling partner.

In a preferred embodiment of the invention, the first coupling side of the coupling unit has the same basic dimensions as the optical plug element to be coupled, in particular receiving openings of the optical plug element being aligned with the receiving openings for the optical waveguides of the coupling unit. This enables a simple threading process when introducing the optical waveguide into the coupling unit: the optical plug-in element serves as a threading aid for locating the small, highly precise receiving openings on the first coupling side of the coupling element.

The second coupling side of the coupling unit preferably has a protruded projection that exposes the receiving openings. This is done via the coupling side End faces of optical fibers, which are introduced into the receiving openings, a beam deflection between the optical fibers and assigned optically active surfaces of the opto-electronic converters.

The optical coupling unit preferably consists of the same material as the optical plug element to be coupled. In particular, the optical coupling unit is made of the same material as the optical fiber end piece of the optical waveguide

Plug element (generally referred to as "ferrule"). The adaptation of the material provides an equal coefficient of expansion in the event of temperature changes, so that the quality of the coupling between the coupling unit and the optical plug element is not influenced by temperature changes.

The receiving openings in the coupling unit for the optical fibers are preferably designed as high-precision bores. It can be provided that the bores are circular in cross section.

The method according to the invention is characterized by the steps: a) providing a multichannel optical plug element with receiving openings for optical waveguides arranged in one plane, b) arranging the multichannel optical plug element on the first coupling side of the coupling unit in such a way that the receiving openings of the optical plug element with the receiving openings of the coupling unit are aligned, c) threading at least one optical waveguide first into the optical plug-in element and further into the coupling unit, and d) gluing the optical waveguides into the receiving openings of the coupling unit. The coupling unit preferably has a recess for introducing adhesive and is placed on an additional auxiliary part with a protruding stud during the threading process in such a way that the optical fibers to be threaded are prevented by the protruding studs from leaving the receiving openings in the region of the recess. The auxiliary part provides a kind of threading aid, which ensures the threading process also in the area of the recess of the coupling unit and facilitates the assembly of the glass fibers.

After completion of the threading process, the optical fibers are chamfered on the second coupling side of the coupling unit in such a way that their end faces direct a beam by 90 ° between the optical fibers and optically active zones of opto-electronic converters of a transmitting and / or receiving unit.

A standard MT ferrule is preferably used as the multi-channel optical plug-in element, since this means that existing ferrules are used

Parts and geometries can be used.

In principle, however, any optical multi-fiber connector or an analog connector can be used as the optical connector element

Auxiliary part can be used.

The invention is described below with reference to the

Figures of the drawing are explained in more detail using several exemplary embodiments. Show it:

Figure 1 is a perspective view of a coupling unit according to the invention;

Figure 2a is another perspective view of the coupling unit of Figure 1, with guide pins being inserted into the coupling unit; ^• Figure 2b is a perspective view of the

Coupling unit of Figure 2a from the other side;

Figure 3 is a perspective view of a

Coupling unit, a threading aid, an optical plug and an optical cable before threading glass fibers into the coupling unit;

FIG. 4 shows the elements of FIG. 3 coupled to one another when the glass fibers are threaded;

Figure 5 is a sectional view of the arrangement of Figures 4 and

Figure 6 is a perspective view of an optical

Plug, a coupling unit and an array of optical-electronic converter.

FIG. 1 shows an exemplary embodiment of a coupling unit 1 for connecting and conducting high-frequency optical signals carried in optical fibers between an optical connector and at least one optoelectronic converter or vice versa.

The coupling unit 1 consists of a one-piece molded plastic body, which is produced, for example, by injection molding. The coupling unit has an upper side la, a lower side lb, two lateral side surfaces lc, ld and one on the left in FIG. 1

Coupling side le and a second coupling side lf on the right in FIG. 1. As shown in FIG. 6, the first coupling side le is used for coupling with an optical connector and the second coupling side lf for optical coupling with optoelectronic converters of a transmitting and / or receiving unit. On the second coupling side lf, the coupling unit forms a chamfered projection 20 that exposes the receiving openings 2, while the first coupling side is ground flat.

In the coupling unit 1, a plurality of receiving openings 2, which are preferably designed as bores, extend parallel in one plane. The bores are produced, for example, in the manufacture of the coupling unit by thin wires inserted into an injection mold. Furthermore, the coupling unit 1 has longitudinal bores 3, into which guide pins or guide pins are inserted according to FIGS. 2a and 2b, which serve to align the coupling unit 1 and the receiving openings 2 or optical fibers arranged therein with respect to an optical plug or other coupling partner ,

From the surface la of the coupling unit 1, two lateral recesses 4 extend vertically in the direction of the bores 3, which have at one end, with the formation of two edges 41, a tapered, narrower region 42 in which the wall of the recess 4 has a kind of thickening 43 ( see FIG. 2b). As can be seen in FIG. 2b, the guide pins 5 to be inserted into the bores 3 each have an annular groove 51, which at

Insert the guide pins 5 from a coupling side after a certain insertion distance into contact with the tapered area 42 with the thickenings 43 of the vertical openings 4, the area of the guide pins 5 adjoining the groove 51 coming into positive contact with the edges 41 of the openings 4 , When the guide pins 5 are inserted, the thickenings 43 are elastically compressed until the annular groove 51 comes to rest against the thickenings 43. In this way, the guide pins 5 are locked and fixed in the longitudinal bores 3. It can be provided that the vertical openings 4 extend from the top la to the bottom lb or extend only from one side to the bore 3.

In Figure 2a it can be seen that a central recess 6 is provided on one side lb of the coupling unit 1, which serves to receive adhesive after insertion of optical fibers into the receiving openings 2 and thereby firmly glue the optical fibers in the coupling unit 1. For this purpose, the recess 6 extends into the area of the receiving openings 2 for the optical waveguides.

Figure 3 shows that for threading several optical fibers of an optical cable into one

Coupling unit 1 required elements. In addition to the optical cable 7, a large number of

Optical waveguides 71, the coupling unit 1 described in FIGS. 1 to 3 and a virgin optical connector 8 and a threading aid 9 designed as a separate part are provided. The optical connector 8 is preferably a standard connector, for example a standard MT ferrule for accommodating twelve optical fibers.

The coupling unit 8 has, in a manner known per se, a housing 81, two guide pins 82 guided in longitudinal bores, a rear sheet metal holding element 83 for holding and fixing the guide pins 82 and receiving openings 85 for receiving the optical fibers 71 of the optical cable 7. A cutout 84 for an adhesive potting for the glass fibers 71 is also provided. In the present case, however, this cutout 84 is not filled with adhesive. The coupling unit 8 serves only as a threading aid for the coupling unit 1 and not for fastening the optical waveguide 71. The centering aid 9 has, on an upper, flat surface 91, a protruding knob 92 which has an upper surface 92a which is arranged parallel to the surface 91 and two angled surfaces 92b, 92c which are inclined in the direction of the surface 91.

FIGS. 4 and 5 show the element arrangement of FIG. 3 when the glass fibers 71 are threaded into the optical connector 8 and the coupling unit 1. The coupling unit 1 is seated on the threading aid 9 in such a way that the protruding knob 92 of the threading aid 9 engages in the recess 6 of the coupling unit 1, approximately to the bottom of the recess in the coupling unit.

The threading process is now such that the optical

Plug 8 is first fastened by means of the guide pins 5 and 82 on the first coupling side le of the coupling unit. Due to the same basic dimensions and by means of the precisely aligned guide pins, coupling takes place in such a way that the receiving openings 85 of the optical connector 8 receiving the optical fibers 71 are aligned with the receiving openings 2 of the coupling unit 1.

It should be noted that the guide pins 5, 82 either on the optical connector 8 or on the

Coupling unit 1 can be arranged. However, they are preferably provided on the coupling unit 1 and fastened there as described in relation to FIG. 2a. Thus, a secure locking is produced by a positive engagement of the coupling unit in the groove 51 of the guide pin 5. The guide pin 5 can be produced in a simple manner by means of a centerless cylindrical grinding machine. The guide pin 5 has a smooth surface, whereby the wear of the coupling partner is reduced.

According to FIGS. 4 and 5, the optical fibers 71 are through the receiving openings 85 of the optical connector 8 and then passed through the receiving openings 2 of the coupling unit 1. As can be seen from FIG. 5, the knob 92 engaging in the recess 6 of the coupling unit ensures that the optical fibers 71, which are glass fibers, are held down for the subsequent openings during the threading process.

After the optical fibers 71 have been threaded in, adhesive is poured into the recess 6 of the coupling unit 1, the optical fibers being fixed. The optical plug 8 is now removed (for example after cutting the optical waveguide) and the end or coupling surfaces le, lf of the coupling unit 1 are polished. Then, as described with reference to FIG. 2b, the guide pins are attached, if not already done.

FIG. 6 shows all the essential elements of an arrangement with a finished coupling unit. An optical connector 8 is coupled to the first coupling side le of the coupling unit 1. It is pointed out here that the optical connector 8, unlike in FIGS. 3 to 5, is a completely assembled connector with inserted optical fibers and a polished end face. The optical connector 8 and the coupling unit 1 are made of the same material, so that the same coefficients of expansion are present when there is a change in temperature and thus improved coupling conditions. On the other coupling side 1f, a receiving or transmitting unit 10 is shown, which has an array of optical-electronic converters 11. These are mounted on a conventional carrier 12 and are electrically connected to a printed circuit board (not shown) by means of a bonding process. Due to the obliquely ground and polished end faces 71a of the glass fibers 71, the optical signals are deflected by 90 ° in a manner known per se and thus strike. the respectively assigned

Transducer 11. Such an arrangement is described, for example, in US Pat. No. 6,250,820.

Claims

claims 1. Coupling unit for optically coupling a multichannel optical plug-in element with at least one opto-electronic converter of a multichannel transmitting and / or receiving unit, the coupling unit comprising: a first coupling side for optical coupling with the multi-channel optical plug element, a second coupling side for optical coupling with the at least one opto-electronic converter and a plurality of receiving openings arranged in one plane for optical waveguides, which run from the first coupling side to the second coupling side, characterized that the coupling unit (1) is formed in one piece, the receiving openings (2) running at least partially in the interior of the coupling unit (1). 2. Coupling unit according to claim 1, characterized in that the coupling unit (1) on its upper or lower side (la, lb) has a recess (6) which partially exposes the receiving openings (2) for the optical waveguide (71), so that an adhesive for gluing optical fibers in the receiving openings can be supplied via the recess (6). 3. Optical coupling unit according to claim 2, characterized by an additional auxiliary part (9) with a from a substantially flat surface protruding knobs (92), wherein the coupling unit (1) on the auxiliary part (9) can be arranged such that the knobs (92) protrudes into the recess (6) of the coupling unit and comes to rest adjacent to the receiving openings (2) for the optical waveguides. 4. Coupling unit according to at least one of claims 1 to 3, characterized in that the coupling unit has means (3, 4) for receiving and latching guide pins (5). 5. Coupling element according to claim 4, characterized in that the coupling unit has two longitudinal bores (3) which each extend laterally to the receiving openings (2) for the optical waveguide, and the longitudinal bores (3) each have a constriction (42, 43) which each serves to lock a guide pin (5). 6. Coupling unit according to at least one of the preceding claims, characterized in that the first coupling side (le) has the same basic dimensions as the optical plug element to be coupled (8), wherein receiving openings (85) of the optical plug element (8) for optical fibers with the receiving openings ( 2) align the coupling unit (1). 7. Coupling unit according to at least one of the preceding claims, characterized in that the second coupling side (lf) has a bevelled projection (20) exposing the receiving openings, with coupling-side end faces (71a) of optical waveguides (71) which enter the receiving openings ( 2) are introduced, a beam deflection takes place between the optical waveguides (71) and assigned optically active surfaces of the optoelectronic transducers (11). 8. Coupling unit according to at least one of the preceding claims, characterized in that the optical coupling unit (1) consists of the same material as the optical plug element to be coupled (8). 9. Coupling unit according to at least one of the preceding claims, characterized in that the Coupling unit (1) consists of a plastic molded body. 10. Coupling unit according to at least one of the preceding claims, characterized in that the receiving openings for the optical fibers (71) are designed as highly accurate bores (2). 11. A method for threading glass fibers into an optical coupling unit according to claim 1, marked by e) providing a multichannel optical plug element (8) with receiving openings (85) for optical waveguides arranged in one plane, f) arranging the multichannel optical plug element (8) on the first coupling side (le) of the coupling unit (1) such that the receiving openings ( 85) of the optical plug element (8) are aligned with the receiving openings (2) of the coupling unit (1), g) threading at least one optical waveguide (71) first into the optical plug element (8) and further into the coupling unit (1) and h) gluing the optical waveguide (71) in the receiving openings (2) of the coupling unit. 12. The method according to claim 11, characterized in that the coupling unit has a recess (6) for introducing adhesive and during the threading process is placed on an additional auxiliary part (9) with a protruding knobs (92) that the optical fibers to be threaded ( 71) are prevented by the protruding knobs (92) from leaving the receiving openings (2) in the region of the recess (6). 13. The method according to claim 11 or 12, characterized in that a standard MT ferrule is used as a multi-channel optical plug element. 14. The method according to at least one of claims 11 to 13, characterized in that the multi-channel optical plug element (8) after gluing the Optical waveguide (71) in the receiving openings (2) of the coupling unit (1) is removed.