DE8706844U1 - Connector for optical fiber - Google Patents

Description

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Bernhard Schmidt GM 8716 DE Rehfeld 8 Ne/Sy

5206 Neunkirchen 1 12 May, 1987

Connector for fiber optic cable Description

The invention relates to a connector for optical fibers, consisting of a sleeve with a through-hole for receiving a sheathed section of the optical fiber, internal guide means for centering a stripped end section of the optical fiber and an inserted spherical lens for bundling the light emerging from the optical fiber.

Optical fibers of the type mentioned consist of a conductor core and a jacket surrounding it, each made of light-conducting material with different refractive properties, as well as a sheath made of plastic or fabric-reinforced material. Such optical fibers are suitable for transmitting laser light for signal transmission over very long distances with little attenuation. On the other hand, it is difficult to design the necessary connection points in such a way that the transmission losses are kept low. This is the purpose of the spherical lenses placed at the respective ends of the optical fibers, the diameter of which is 20 to 100 times larger than that of the light-conducting core of the optical fiber. The spherical lens is

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to the end of the optical waveguide so that it is as close to the focal point of the lens as possible. This scatters the light into an approximately parallel beam with a significantly larger cross-section, so that an axial distance and/or a radial offset to a corresponding lens of a mating connector only leads to relatively low percentage losses, which are significantly lower than with a direct coupling of two optical waveguide ends. The losses at the ball lens due to reflections are insignificant and can be further reduced by appropriate coating. In any case, the precise adjustment of the Optical fiber end in the focal point, as well as the parallel alignment of the optical fiber end.

US 4,265,511 discloses a connector for optical fibers, in which the optical fiber end is connected to a light source and inserted into a connector pin in order to fix the optical fiber end axially in relation to the spherical lens, whereby the emerging light is captured on a ground glass screen or the like and the desired position of the optical fiber end in relation to the spherical lens is determined by checking the light spot diameter on the ground glass screen. The optical fiber is glued into the connector pin in the determined position. Means are also provided here for subsequently aligning the connector pin parallel within the connector. Although a connector pin of this type is already described as a simplified construction, it is clear from the method described that the adjustment effort required for mass production of connector pins, for which there is an increasing demand, cannot be justified.

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The present invention is based on the object of creating a connector for optical fibers of the type mentioned at the beginning, which can be manufactured and assembled using simple means and which enables the optical fiber end to be adjusted to the focal point of the ball lens used with high and lasting accuracy, even in series production. This object is achieved by an annular spacer element which, on the one hand, rests in a defined manner on the ball lens and, on the other hand, lies flat on the guide means in the plane of the optical fiber. This makes it possible to assemble the guide means, the spacer ring according to the invention and the ball lens to the stop with precise adjustment of the optical fiber end to the focal point of the ball lens. Conventional assembly forces can be used here, with the assembly paths resulting from the thickness of the spacer ring, which must be manufactured precisely beforehand. The alignment of the optical fiber end with the contact surface of the guide means is achieved in a known manner by grinding both parts that have already been glued together. The production of the *■ spacer rings can be carried out on precision lathes known

Art, whereby on a corresponding rod made of Heusilber first the spherical cap surface and the Inner bore must be turned and then the disc

from the bar in the desired thickness. These are components whose costs are relatively low compared to

time saved for complicated adjustment procedures. ■ Turning the

The so-called spherical cap is made using a diamond forming tool. To simplify matters, a conical contact surface is also possible, the opening cone and opening diameter of which must be precisely maintained on the front surface of the spacer ring.

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For the distance of the optical fiber end to the surface
the ball lens a tolerance of +/- 5 μgr; is required,
to guarantee the desired damping values, which without
further by a manufactured with known tools
Spacer ring must be observed.

The necessary distance from the fiber optic end to the |

Spherical surface, i.e. the focal length of the lens can be in §

be determined empirically in a single process by |

the thickness of a sample disc is changed until 1

optimal f on a plug equipped with it

Transmission ratios to an optimized mating connector!

However, determining the optimal distance is

also possible by purely mathematical means. I

According to a particularly preferred embodiment, the { Ball lens pressed into a lens sleeve into which a "j Plug pin can be inserted from which the f Management tools are also included. The latter are also

preferably without adhesives in the \

Plug pin pressed in. Before mounting the lens sleeve \

and connector pin in vertical position, a

Spacer element inserted into the lens sleeve, whose \ Diameter in relation to thickness is so large that j

its orientation within the lens sleeve is not \

can change unintentionally. The spacer ring is

hereafter with its spherical surface on the sphere surface

to Hegen, whereby a small radial play \

is present. Then the plug pin must

introduced and placed on the flat surface of the

Distarizeiementes. Plug pin and Lens sleeves are glued in this position or &kgr;

jammed and can then be connected with an I

Cap sleeve of a quick coupling or the like. An embodiment according to the subject matter of the invention can be seen from the attached drawings.

Fig. 1 shows a complete connector.

with a glued-in optical fiber

Fig. 2 shows a spacer element as a detail, in two versions

Figure 1 shows a connector according to the invention for an optical waveguide 13, which consists of a connector pin 1, which receives two guide sleeves 2 at one end as a guide means, and a lens sleeve 3 into which a ball lens 5 is inserted. A through hole 6 in the connector pin 1 has a middle section, which serves to glue in and "fix" the optical waveguide sheath 14, a section widening towards one side for inserting the optical waveguide 13 and a section widening towards the other end for receiving the guide sleeves 2. Each of the guide sleeves 2 has a capillary bore 7 and an insertion funnel 8, whereby the arrangement of two identical sleeves in pairs improves the axial alignment of the stripped optical fiber end 15. The front sleeve protruding from the connector pin 1 is ground flat together with the front end of the optical fiber end 15. The spacer element 4, which has radial play, rests on its front surface 9 and rests against the spherical lens with its second dome surface 10, which has the same curvature as the spherical lens. The spherical lens 5 is glued into the lens sleeve 3, but can also be pressed into it exclusively.

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A particularly precise axial fixation of the ball lens 5 within the ball sleeve 3 is in itself irrelevant. The ball lens 5 is preferably completely protected within the lens sleeve 3. After plugging the connector pin 1 and the lens sleeve 3 into one another, these parts are glued or clamped together. The spaces filled with adhesive 17 are laid out in the illustration and essentially concern the insertion funnels 8 and the extended section 13 of the connector pin.

In Figure 2, the shape of the spacer element 4 can be seen as a detail, whereby in the embodiment according to Figure 2a a spherical cap surface 10 is provided on one side and a flat surface 11 on the other side, and overall a ring body with an inner bore 12 is formed. In the embodiment according to Figure 2b, the cap surface is replaced by a conical surface 16. The intended center of the spherical line is designated with ₄ M.

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Bernhard Schmidt GM 8716 DE

- Rehfeld 8 Ne/Sy

5206 Neunkirchen 1 12 May 1987

Connector for optical fiber

Reference list

1. Connector pin

2. Management tools

3. Lens sleeve

4. Spacer element

5. Ball lens

6. Inner bore

7. Capillary drilling

8. Insertion funnel

9. Frontal surface

10. Calotte surface

11. Plane surface

12. Inner bore

13. Optical fiber

14. Sheathing

15. Conductor end (stripped)

16. Conical surface

17. Adhesives

Claims (10)

&bull; · ■ · Bernhard Schmidt GM 8716 DE Rehfeld 8 Ne/Sy Neunkirchen 1 12 May 1987 Connectors for optical fibers Protection claims 1. Connector for optical fibers, consisting of a sleeve with a through hole for receiving a coated section of the optical fiber, internal guide means for centering a stripped end section of the optical fiber and an inserted ball lens for bundling the light, characterized by an annular spacer element (4) which on the one hand rests in a defined manner on the spherical lens (5) and on the other hand lies flat on the guide means (2) in the plane of the optical waveguide end (15). 2. Plug according to claim 1,
characterized, that the spacer element (4) has a dome-like ring surface on the sphere side, which has the same curvature diameter as the spherical lens (5). 3. Plug according to claim I ₁
characterized, «4 *· · · ·· It is ItIl 14 I * · · ti ** I ill·«··· · · I M *l · * Il · that the spacer element (4) has a conical ring surface on the spherical side, which rests on the spherical lens (5) at a defined diameter. 4. Plug according to one of claims 1 to 3, characterized in that the guide means (2) are ground flush with the stripped optical fiber (15) on the ball side. 5. Plug according to one of claims 1 to "4, characterized in that that the guide means (2) comprise two guide sections arranged axially spaced from one another for centering and axially aligning the optical waveguide end (15). 6. Plug according to one of claims 1 to 5, characterized in that that the guide means (2) consist of two identical inserts lying one behind the other, each with a capillary bore (7) and a conical insertion funnel (8) adjoining it. 7. Plug according to one of claims 1 to 6, characterized in l * i i i i i t IIIII It ■ ■ i i #i &igr;&igr; i » it it t , j |,&igr;.< It · in Il Ii "' '< ■ that the spacer element (4) is held in the plug in a radially floating or self-aligning manner between the guide means (2) and the ball lens (5). 8. Plug according to one of claims 1 to 7, characterized in that; that the guide elements (2) are inserted into the plug in a section of enlarged inner diameter of the through-bore (11) adjacent to an inner collar. 9. Plug according to one of claims 1 to 8, characterized in that the ball lens (5) is pressed into the plug. 10. Plug according to one of claims 1 to 9, characterized in that the plug is made up of several parts and the ball lens is held in a lens sleeve (3) that can be pushed onto a plug pin (1) that accommodates the guide means. ·■t Kt If It C · ICCt ItC ■ ■ C to Il · · · t .·