DE2516858C2 - Detachable plug connection for optical fibers - Google Patents

Description

the diameter of the bore of each plug (2.12) is larger than the outer diameter of the respective optical fiber (1, 11), by an amount which is greater than fitting tolerances,

2. the end of the optical fiber in this bore centered on the circumferential surface of the connector is arranged and fixed in this (at 6, 13). and that

3. the Stetker (2, 12) by means of a spring (4) or a screw sleeve are held in the fitting sleeve (3).

2. Plug connection according to claim 1, characterized in that the Pdßhülse (3) has a bore ₂ , p, 8) for the supply of a suitable immersion fluid.

3. Plug connection according to claim I or 2, characterized in that the plug (2, 12) on liren end faces (2, 12) with a dust catching groove (5) »See sii * '

4. A method for producing a connector according to tinem of the preceding claims, characterized marked that of sinen? cylindrical part is assumed, the outer diameter of which is greater than the inner diameter of the fitting sleeve, and I was by an amount greater than Fit tolerances that a bore is formed in the cylindrical part, the diameter of which is larger than the outer diameter of the optical fiber to be used is larger by an amount is, as fitting tolerances, that inserted into the bore egg "fiber end of the optical fiber and without Further radial positioning is attached therein, ■ nd that then the cylindrical part is centric to the each radial fiber position is reworked for fit.

5. The method according to claim 4, characterized thereby. that for reworking on fit the cylindrical part is attached to the coordinate table of a universal milling machine and the spindle with the tool is set up on the fiber center with the aid of a centering microscope and then the cylindrical part is reworked on the machine.

6. The method according to claim 4 or 5, characterized in that the optical fiber by KIe-Sung or pinching in the bore of the cylindrical part is attached.

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The present invention relates to a detachable plug connection for optical fibers according to the preamble of claim 1.

Easily detachable plug connections are required for the low-loss connection of optical fiber ends.

When coupling multimode fibers with a circular cross-section and a stepped refractive index profile certain tolerances must be observed with regard to the following parameters:

Distance between the fiber end faces, mutual tilting of the fiber ends, lateral offset of the fiber axes and surface properties of the fiber end faces, as well as normality of the end faces to the fiber axis. The transmission of the fiber-fiber coupling depends on the above parameters, as well as on the fiber parameters core radius and Acceptance angle.

In known plug connections, the mechanical tolerance requirements are met in that -Jie free, with the best possible end faces Fiber ends are guided against one another in grooves or holes with close tolerances. For example this is in the plug connection according to DE-OS 23 52 874 the case that a plug connection of the aforementioned Kind of represents

in practice, however, there are some disadvantages. So are difficult to manufacture, tightly tolerated deep holes with the diameter of the fiber are necessary, or a sensitive merging of the Fiber ends by hand, possibly even with the help of a micromanipulator. In other cases it is before coupling, at least one free fiber end of about 0.1 mm diameter is present Tampering can easily be damaged or soiled.

In particular, when the fiber ends are brought together in narrow grooves or bores, there is a risk of that existing dust particles are collected in the guide elements and onto the fiber ends arrive so that the coupling losses are increased in an uncontrolled manner.

The object of the present invention is to provide a detachable plug connection that can be produced without a micromanipulator. at dt / the risk that existing dust particles get on the fiber ends, is reduced, and in which the connector with the centrally fastened fiber can be produced in a simple and expedient manner.

This task is based on a connector of the type mentioned by the im characterizing part of claim I specified features solved.

Preferred and advantageous embodiments of a plug connection according to the invention are based on Claims 2 and 3 emerge.

A particular advantage of such a Steckverbindeng is to be seen in the fact that they are without microscopic Guide elements and thus easy to manufacture and robust and uncritical in handling.

In particular, a plug connection according to the invention can be particularly advantageously made according to the method manufacture according to claim 4, which is characterized by the particularly simple and unproblematic centering an optical fiber in the connector.

Preferred embodiments of this method according to claim 4 emerge from claims 5 and 6. A proposed plug connection can advantageously be expanded to a linear arrangement of parallel plugs, the stacking of such Parallel connector continues to provide a very compact connection for a larger number of individual fibers. So a coupling element for 100 individual fibers with dimensions of 60 60 χ 32 mm can easily be implemented.

The identical assembly of the individual fibers also has the advantage that each fiber is individually can be exchanged or repositioned without disconnecting the other connections.

Another advantage is that with a stepped refractive index professional! By illuminating the fiber, it can be centered directly on the core-cladding interface of the fiber, so that manufacturing asymmetries of the fiber are not included. Therefore, the releasable plug connection according to the invention is particularly suitable for Einmaterialfasern & jt, where the exact centering of the fiber core according to experience difficult to outer sheath, as in a compact core'Vlantel fibers.

In the following the invention is described with reference to the figure, for example, in which an embodiment a connector according to the invention is shown schematically.

In the figure, 1 and 11 are two optical fibers to be connected, for example multimode optical waveguides of the core-clad type. Each fiber 1, II is surrounded by a connector 2, 12, with their End faces collide. The enimaged ends 6.13 of the optical fibers 1.11 are by means of Klebu..gen in the corresponding plugs 2, 12 attached. 5 with a dust catching groove is referred to, which is the end faces of the Surrounds connector

3 with a cylindrical metallic fitting sleeve is referred to, which the two plugs 2, 12 concentrically surrounds. In addition, a suitable spring 4 and / or a suitable screw sleeve is used for holding the plug in the sleeve. 7.3 bores are designated for the supply of a suitable immersion liquid, by securing the fiber in the connector by increasing the adhesive surface and partially Strain relief of the fiber is achieved.

The only critical requirement for the realization of the specified connector is the centering of the Fiber end into the connector. Two methods for inexpensive mass production are suitable for this.

1. The cylinder. ical connector part, which provides the fit in the fitting sleeve, is first made with approx. 0.2 mm excess. The fiber end is then inserted into the hole provided for it, without any further radial positioning, and fastened there by gluing or squeezing. If the plug is to be filled with an optical immersion medium later, it is sufficient. Insert the broken fiber ends as far as possible up to the level of the connector end face. Otherwise the fiber cortex must be ground and polished together with the end face.
The fiber end thus prepared is then reworked on the cylindrical guide part centrically to the respective radial fiber position for fit, z. B. in such a way that the connector is attached to the coordinate table of a universal milling machine and the spindle with the tool is set up on the center of the fiber with the aid of a centering microscope. Machines of this type customary in workshops already deliver an accuracy of ± 5μΐτ).

ίο 2. For a centric attachment of the fiber ends the guide cylinder already worked on the fit. Under a reflected light microscope, its eyepiece contains two perpendicular ocular micrometers, the connector and fiber are positioned axially and with the help of two independent 3-coordinate micromanipulators centered to one another and then connected to one another by gluing or squeezing. Depending on the size of the object field and the resolution of the microscope, the centering accuracy in this method is ± 2 μίτι.

The c ical centering, which is necessary in both cases, can be automated if larger quantities are required are made using the optoelectronic positioning methods commonly used in semiconductor manufacturing. The effort for the tolerances of the fitting sleeve, however, is comparatively small. So are fits with a radial Offset of a maximum of 4 μΐπ and a limitation of the Tilt angle of ± 54 can be achieved without difficulty Spring force or screw sockets are guaranteed.

The advantages of this connector are particularly evident when it is possible to use prefabricated ones Fiber lengths to be used. The fiber ends need

j; then no longer prepared when assembling the connector and To be optically checked if they are sealed after manufacture, for example with a Protective cap are provided. Dirty fiber ends can be safely removed thanks to the robust metal frame getting cleaned. The problem that when joining the connector dust from the fitting sleeve reaches the fiber end, occurs with the invention Pin · .Tbinding not undone. From the in relation to This is because the total area of very small light passage area has a very low statistical probability for the presence of a foreign particle in the optical beam path. This danger can persist can be completely avoided by attaching dust grooves.

The plug connection is suitable for fine fibers. whereby for fibers whose cross-sections are only a few Has symmetry elements, the optical readjustment by simply marking the connector on a Minimum is reduced.

1 sheet of drawings

Claims (1)

Patent claims: 1. Detachable plug connection for optical fibers, especially for multimode optical waveguides, consisting of a cylindrical, metallic fitting sleeve and two cylindrical, machined to fit, into the fitting sleeve from both sides inserted plugs, each having a bore for the central reception of an optical fiber, characterized in that IO