DD206238A1 - METHOD FOR PRODUCING A Y-BRANCH - Google Patents

Abstract

THE OBJECTIVE OF THE INVENTION IS THE LOSS OF PREPARATION OF Y-SHARES FROM LIGHT GUIDES USED IN LIGHT-LINE APPROACH TECHNOLOGY, WHICH IS REPRODUCIBLE AND RATIONAL. THE TASK IS TO INDICATE A PROCEDURE FOR THE MANUFACTURE OF Y-SUBSTANCES FOR WHICH A LITTLE NUMBER OF WORKING SIZES IS REQUIRED AND, IN THE ABSENCE OF A REDUCED MECHANICAL PRACTICE, A HIGH LEVEL OF COUPLING IS ACHIEVED. THIS IS MADE THAT THE HEADS OF TWO IN SEPARATED HOUSING BOXES ARE POWERED AND FORMALLY EMBEDDED IN LIGHT GUIDES, THAT, AS THE HOUSING KOERPER COMPOSES, THE LIGHT LEADERS SUPPLY SPITZWINKLIG TO EACH OTHER. AFTER BONDING OF THE TUBE LAYERS, BY TREATING THE HOUSING BODY, A COMPOSED COMMON CROSS-SECTION SURFACE OF EITHER LIGHT LEADER IS OBTAINED AND CONNECTED TO A PLANE HEAD LAYER OF A THIRD LIGHT GUIDE THAT A Y ARISES.

Description

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Berlin, 12. 07. 1982 ze-scht 29170 / if3

Applicant Dr, -Ing «Bernd Porbrig Hans-Dieter Kühl

Method of making a Y-branch

field of use

The invention relates to a method for producing a Y-branch, in which the reproducibility increases and the Lieht-yerluste be lowered and which finds application in the optical fiber message technology.

Characteristic of known technical solutions

Y-branches for light guides are known for example from DE-AS 2 205 996, DE-OS 2,738,050, DS-OS 2,712,809 in various variants »Should these branches in each case with the Lichtleiternachriehtentechnik, conventional light guides whose core diameter between 5 to 80, in order to be realized, their production requires a high adjustment effort,

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which moves at the limit of the possible. It is known to adjust the three optical fibers required for the Y-branch after a pretreatment by grinding or by etching to each other and to weld together, see DE-OS 2,717,535, G 02 B 5/14.

The reproducibility of the optical parameters is low and the losses relatively high due to the difficult to control diffusion processes in welding, which lead to changes in the refractive index profile of the optical fibers, cf. F. Auracher, Principles and Properties of Branches for Multimode Fibers, frequency J3 £ (1980 ) 2, pp. 52-57.

In another known Y branch, the three required for the Y branch light guide are individually brought in GehäuseblScken in the final shape and assembled under visual control, see, DS-OS 2 738050, G 02 B 5/14. Y-branches produced in this way are low-loss, but the production of such branches is a considerable expense due to the large number of operations.

Although known Y-branches executed in planar technology can be produced reproducibly, cf. DS-OS 2 827 005, they have relatively high overall losses when coupled with step-indium optical fibers (^ 1.5 dB), which occur when using in of optical fiber message technology nearly treble gradient index optical fibers, cf. "a" a, O, "Auracher, ·. ·".

Aim of: invention

The aim of the invention is to reproducibly and efficiently produce low-loss Y-branches of optical fibers used in optical communications technology.

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Essence of the invention

The object of the invention is to provide a method for producing Y-branches, in which a small number of operations is required and despite a reduced mechanical precision, a high degree of coupling is achieved »It is assumed that the ends of two light guides in a certain length individually embedded in two existing housing bodies frictionally and positively.

According to the invention, this object is achieved in that a surface, each body is ground and polished at an acute angle to the optical axis of the light guide such that a flush cut surface of the light guide cross-section is formed and that the polished surfaces of the housing body under consideration of a geometric overlap of both cut surfaces the light guide and are pressed together with the addition of a transparent adhesive and adjusted to each other such that the ratio of the proportion of light emerging from the cut surface of the core of the one light guide and the light entering the cut surface of the core of the other light guide results in a desired optimum, and the one end of the glued together housing body is sanded and polished perpendicular to the adhesive surface until the pointing composite end face of both light guides ^ define a desired circular cross-section rten diameter results and that the plane end face of a third light guide corresponding cross-section is added to the composite end face of the two light guides, that the sum of the proportions of the light emerging from the two light guides in the third light guide reaches a maximum. The problem is a reliable thermally stable. Introduction of the multi-coated layers

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Optical fiber in the housing body. It is therefore expedient to freely move a part of the light guide emerging from the inner sheath within a cavity of the housing block, while the outgoing end continues to be non-positively and positively connected to the housing body over a certain length. The geometric overlap of the two cut surfaces may differ depending on the desired optimum of entry and exit of the light at the cut surfaces, so that different divider ratios are achieved. The adjustment movement may be a mutual, radial or axial displacement to the optical axis of both housing bodies.

embodiment

On the basis of reproduced in the drawing embodiments, the invention will be explained in more detail. In the drawing show:

Pig, T is an enlarged schematic representation of a housing body with embedded light guide, - partially in section

Fig. 2 is a schematic enlarged view of two together glued housing body, partially in section

Fig. 3 is a functional diagram

Fig. 4 is an enlarged sectional view of FIG. 2 and

Fig. 5 is a schematic enlarged view of a composite of three optical fibers Y-junction in the vicinity of the branch point.

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FIG. 1 shows a housing body 1 made of a transparent thermoplastic, in which a light guide 2 is embedded with its inner shell 3 and outer shell 4. At the exit of the light guide 2 from its inner shell 3, a piece of the light guide is slightly curved in a cavity 5, while the outgoing end of the light guide 2 is embedded in a certain angle to the flat longitudinal surface in the housing body 1. The curvature of the light guide allows a thermally stable lead out of the light guide from the housing body 1. The flat longitudinal surface of the housing body 1 is ground and polished until the cross-section of the light guide 2 comes to light in a specific area S. The amount or thickness of the material to be removed is not critical within wide limits, so that mass processing is possible for example, by embedding a plaque In the same way, with a second, not shown in Fig, I housing body, moved. Both housing bodies are then 3 ig. 2 assembled, adjusted and glued under pressure. The thickness of the adhesive layer is less than 0.5 / am *

Pig., 2, shows two housing body 1; 11 with the forward end outer sheaths 4, 4-1 of two unspecified optical fibers whose abutting ends are partially shown in section. The sheath of the two light guides are denoted by 7 »71 and the cores 8, 81. The direction of the light flux is indicated by arrows. The adjustment of the two cross-sectional surfaces of both light guides can be done by axial displacement to the optical axis. Favorable is also a radial displacement transverse to the optical axis. For this purpose, the two housing body by means

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The further the pin 9 is removed from the junction of both light guides, the lower the influence of dimensional deviations when connecting both housing blocks .. As an adjustment criterion, the ratio of the cut surface of the one serves Light guide exiting light and entering the cut surface of the core of the other light guide light, which is measured in a manner not shown. The adjustment process is completed when this ratio reaches the optimum value, which is a minimum in the case of a 1: 1 Y branch «. This means that the crosstalk is maximum * This happens relatively quickly, so that the transparent adhesive can not cure in this time * The pressure of the two housing body 1, 11 against each other is about 6 p / mm » When producing patterns with optical fibers of 50 to achieve core diameter, a coverage accuracy of - · <1 / um has been achieved.

FIG. 3 shows a functional diagram of the light flux distribution φ in the core 81 of the optical waveguide embedded in the housing body 11, illustrating the adjustment process, wherein χ indicates the direction of displacement parallel to the optical axis.

The light flux <fi- is read in relative units. With perfect coverage, that is, χ = ο, the luminous flux f is a maximum. Analogous behavior is evident in the case of radial or axial displacement relative to the optical axis. The corresponding optimal characteristics are easily measurable, so that there is a relatively simple adjustment, which is also relatively fast.

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Pig. 4 shows an exact overhanging of the two optical fiber cores 7, 71 and of both optical fiber sheaths 8, 81, according to section A ♦ / A A in Pig. 2, which corresponds to a divider ratio of 1: 1. Purely deviating divider ratios are the two housing bodies 1, 11 to move relative to each other ·

After the curing of the transparent adhesive, the two housing bodies are ground down on the front side until a common plane end surface forms, which, for example, in the cross-section of the pig. 4, section A »/" A, corresponds ·

The sharper the angle at which both light guides converge, the more tolerant the relevant grinding process is * For example, a Y replacement of the two cross sections of the two optical fiber cores 8, 81 leads to each other from 20 to

ο at an angle of 1.5 and a core diameter, from 50 / to a loss of light power of 0.2 dB. The thus created common plane end surface of both light guides 1, 11 is optically contacted with the plane end surface 'of a third housing body 10 embedded-third non-designated light guide, for example. By gluing, see. Pig. 5. The core of the third optical fiber is denoted by 12 and the clad by 13 «. In place of another housing body can also find a Klebmasse.Verwendung. The branch point at which all three light guides collide is denoted by 14 »

The third light guide is then correctly adjusted for the two other light guides if a maximum of light arriving from the two other light guides is measured in the third light guide.

Claims (1)

242480 3 Invention claim "A method for producing a Y-branch, in which the ends of two light guides in a certain length individually in two housing bodies are positively and positively embedded, characterized in that a face of each housing body (1; 11) at an acute angle to the optical axis the optical waveguide is ground and polished so that a flush cut surface of the light guide cross section is formed and that the polished surfaces of the housing body (1, 11) are pressed against each other and adjusted to each other, observing a geometrical overlap of both cut surfaces of the light guides and adding a transparent adhesive the ratio of the proportions of the light emerging from the cut surface of the core (7) of the one light guide and the proportion of the light entering the cut surface of the core (71) of the other light guide gives a desired optimum and that one of the sockets of the glued together housing body, perpendicular to the adhesive surface as far as ground and polished until the pointing composite end face of both light guides results in a desired circular cross-section of defined diameter and that the plane end face of a third optical fiber corresponding cross-section is added to the composite end face of the two light guides such that the sum of the proportions of the light emerging from the two light guides reaches a maximum in the third light guide * 5 pages drawings *