DE2905360A1 - OPTICAL COUPLING DEVICE - Google Patents

Description

29Ü5.360

'ATENTANWÄLTE ZENZ & HELBER ■ O 43OO ESSiN 1 · AM RUHHiSTEIN 1 · TEL .: (O2O1) 412687 Page - ff- T 90

TRW, INC.
10880 Wilshire Blvd., Los Angeles, California 90024, V.St.A.

Optical coupling device

The invention relates to an optical coupling device with at least two optical fibers, the ends of which can be optically coupled via the coupling device.

In recent years, optical fiber technology has developed rapidly. Optical fiber systems are found in many areas increasingly used, for example in the fields of telephony, community antenna systems for data transmission, industrial process controls, space and marine communication systems.

As is well known, there are various causes of poor coupling between the fiber ends. For single fiber connections the causes of the error relate to the orientation, arrangement and geometry of the ends of the individual optical fibers at their interface or junction.

For example, in the event of transverse and lateral misalignment of the ends of the fibers to one another results in a considerable loss of signal at the interface, which is caused by increasing lateral displacement grows.

In addition, a longitudinal spacing of the fiber

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end or a shift in the longitudinal direction to significant signal losses, which with increasing distance of the grow on butt ends.

The spacing or separation of the fiber ends leads primarily to one out of the end because of the natural divergence light beam exiting an optical fiber leads to a considerable loss of signal. Additional losses can be occur when the ends are separated by a medium which does not have the same index of refraction how the fiber has; the resulting losses have a cumulative effect.

It has been shown that axial or angular Misalignments contribute significantly to the deterioration in transmission efficiency, with the losses increase with the angle between the adjacent end faces of the optical fibers. The losses due to Fresnel reflection and those introduced by lateral displacement Signal loss is also cumulative and contributes significantly to the overall loss the coupling of optical fibers.

Two types of optical cables are currently in use, namely bundle cables with multi-fiber conductors, the all carry the same optical signal, and single-fiber cables in which each single fiber (if several fibers are present in the cable) form a separate signal channel.

Another coupling problem with conventional optical cable couplers is that of significant degradation of efficiency occurs when optical cables with a large diameter are connected to cables with a smaller diameter are to be coupled. Even with a precise axial alignment of the cable with a large cross-section to that of the

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small cross-section results in considerable losses at the periphery of the cable with smaller cross-section when light should be transferred from the larger cable to the smaller cable.

Both with the multifiber ladders and with the single fiber ladders There is a need for a device which enables switching between either single fibers or groups of coherent or bundle fibers is effected in an accurate and reproducible manner when the connected cables are not accurate have similar diameters. It is also desirable to provide a coupler in an optical relay switch, which in a simple manner a fiber with at least one optical fiber pair in and out of optical alignment without damaging the fibers at their intermediate interfaces. Because of the difficulty of the Moving a first fiber into and out of alignment with a second fiber in an accurately repeatable manner It is also desirable to configure a fiber optic relay switch to have a pair of fiber ends couples and separates without having to move one fiber end in relation to the other. Finally is in one fiber optic relay switch a coupling device desired, which the optical coupling of a first Fiber end with one end of a second fiber allows without the two ends to be coupled in each case in butt joint to have to bring.

It is therefore the object of the invention to provide an optical coupling device which can also be used as an optical relay switch To provide that with a simple structural design

an effective coupling between two mutually spaced fiber ends and a practically wear-free one and reliably switching the optical signals from a first to a second fiber or to

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a plurality of fibers and enables coupling with high efficiency even if the ends of the Fibers to be coupled are not precisely matched to one another, smooth and normal to the axis of the optical fibers Have end faces.

Starting from an optical coupling device of the type specified at the beginning, the invention proposes to solve this The task is that each end of the two fibers on a concave reflective surface of a reflective component is directed and the concave reflective surface is so formed and arranged relative to the two fiber ends is that an optical signal in one of the two fibers reflects on the end of the other fiber and focuses on this will. This coupling device can be used as a fiber optic relay switch in that the reflective component is movably supported, the reflective surface in a first position of the reflective component the end of the first fiber couples to the end of the second fiber and in a second position the reflective Component couples the end of the first fiber to the end of a third fiber so that the optical signals between fiber pairs can be switched.

In the following the invention with reference to ir / the drawing illustrated embodiments explained in more detail. In the drawing show:

1 shows a schematic representation of a first exemplary embodiment that can be used as a relay switch optical coupling device;

FIG. 2 shows a schematic representation of the optical coupling device according to FIG. 1 in a second position of the reflective component;

3 shows a schematic representation of a modified one

Embodiment of the optical coupling device,

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wherein the reflective member is in a first position;

4 shows a schematic representation of the modified exemplary embodiment of the optical coupling device, wherein the reflective member is in a second position;

5 shows a schematic representation of another exemplary embodiment the optical coupling device, which is used for coupling a first optical fiber with optical fibers of different Diameter is used;

6 shows a schematic representation of partially cut fiber ends of different sizes, which can be used in the embodiment of FIG. 5;

7 is a side view of a preferred embodiment.

shape of the reflective component under schematic Representation of the optical fibers used with this;

8 shows a side view of the reflective component in a second position; and

FIG. 9 is a vertical section along the line 9-9 in FIG.

In Fig. 1 is a first embodiment of a reflective optical coupler and relay switch shown schematically, in which in principle a reflective component 20 and a plurality of optical fibers 22, 24 and 26 are provided.

Each of the optical fibers 22, 24 and 26 is shown schematically for purposes of illustration. That is, in each of the optical fibers 22, 24 and 26, the cladding is shown in section, that is, shown in dashed lines, while the fiber core itself is white is shown when the fiber is not light conducting. By doing the last-mentioned case, the light rays passing through the core are shown schematically. The optical fiber 22, which receives light from the direction of arrow 28, therefore contains a schematic representation of the light beam path, which is indicated at 30, and the fiber 24 which

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Transmitting light in the direction of arrow 32 contains lines 34 which illustrate the transmission of light through the fiber core

As can be seen in Fig. 1, the reflective component is 20 curved, and the curved shape is intended to illustrate a concave, three-dimensional surface, which is preferably on the inside of a spherical wall is attached · It should be noted that the reflective surface is the same should have concave curvature in the transverse directions.

The optical fiber 26 in Fig. 1 is shown with a white core, because it does not transmit any light in the position of the reflective component shown. The optical fibers 22, 24 "and and the reflective member 20 are disposed within a closed container, preferably with a Liquid is filled, the refractive index of which is matched to that of the core of the fibers 22, 24 and 26. The free End 36 of optical fiber 22 is near the concave reflective surface 38 of the reflective member arranged and directed towards this. Note that the light beam transmitted through the optical fiber 22 after its exit from the end 36 of the optical fiber 22 has a natural divergence »The divergence is indicated by the lines 40, which the radiation cone of the beam emerging from the end of the fiber 22 illustrate. When the beam falls on the reflective surface 38, it will be due to the concave configuration This surface is bundled, i.e. reflected back in a convergent manner, as illustrated by the converging lines 42 and focused at the end 44 of the optical fiber 24. The reflective component 20 therefore acts as an optical one Coupler between the ends of optical fibers 22 and 24 and causes one in the direction of arrow 28 in the optical fiber 22 signal entering through the optical fiber

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24 is transmitted and derived in the direction of arrow 32

The coupling device shown in Fig. 1 can be used as a relay switch by changing the radius of curvature of the surface 38 is rotated such that the diverging light beam from the fiber 22 onto the fiber 26 in the in Fig. 2 is reflected way.

As can be seen in FIG. 2, this converges from end 36 the light beam emerging from the optical fiber 22 in the second position of the reflective component 20 Reflection on the reflective surface 38 according to the lines 46 such that it is at the end 48 of the optical fiber 26 is focused. The beam is then transmitted through optical fiber 26 in the direction of arrow 50.

It can therefore be seen that the reflective coupling member 20 is used not only for transmitting an optical signal from one fiber end to another, but also by moving to switch from one fiber path to another can be used.

In Figures 3 and 4 is another embodiment of the optical coupling device useful as a reflective optical coupler and relay switch, shown which further comprising means for branching off part of the signal transmitted from the first fiber to the second fiber.

The coupling device of Figures 3 and 4 has a reflective coupler 60, a first optical fiber 62, a second optical fiber 64 and a third optical fiber 66.

The reflective coupler 60 consists in principle of a transparent component with a partially silver-plated concave

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Surface 68, which is the major part of one of the optical Paser 62 exiting beam 70 is reflected, but a portion 74 passes through. The silvered surface 68 of the reflective coupler 60 also has a three-dimensional concave configuration, e.g. Bullet. In a first position, the surface 68 enables the reflective component to be focused from the optical Fiber 62 exiting diverging beam 70 onto the end of the optical fiber 64, through the through Lines 70 and 72 indicated train. Since the surface 68 is partially silvered or mirrored, part of the Light beam pass through this area in the manner shown by the dashed lines 74. That The bundle of rays within the lines 74 runs to a lens 76, which the remaining bundle of rays corresponding to the lines 78 bundles and focuses on one fiber. Lines 78 and fiber 80 are also shown in dashed lines.

When the radius of curvature of the reflective surface 68 is angularly displaced by movement of the reflective member 60 the light beam emerging from the fiber 62 is reflected along the lines 62 and focused on the fiber 66 It should be noted, however, that the small amount of light will still pass through the reflective surface 68 and along the Lines 74 to the lens 76 pass through, which latter converge the part of the light beam falling through the component 60 leaves and focused on the fiber 80.

The optical coupling device shown in FIGS. 3 and 4 therefore not only allows the simple coupling and relay switch function, but also makes it easier Part of the signal fed through the optical fiber 62 is branched off before it reaches the optical fiber 64 or achieved. The proportion of the partial signal branched off from the main signal source depends on the degree of mirroring of the surface 68 dependent.

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In FIG. 5, an optical fiber 90 is shown in combination with a reflective component 92. The reflective component 92 carries a concave reflective surface 95 which is similar to the reflective surface 38 of the reflective component is formed in Fig. 1.

The light beam emerging from the end of the fiber 90 diverges according to the lines 94 in the direction of the concave surface 95. After reflecting on the reflective Surface of the reflective component 92, the beam is focused in the manner illustrated by the lines 96, according to the distance from the reflection surface to different diameters, as indicated by points C, B and A along the beam path. The one with Point designated F is the point at which the beam is focused on a point.

In Fig. 6, the ends of an optical fiber are schematically shown 98, an optical fiber 100 and an optical fiber 102 are shown. Each of these fibers contains a core that makes the The diameter of the beam 96 at points A, B and C in FIG. 5 corresponds. In other words, if the optical When fiber 98 is placed between the locations labeled A in FIG. 6, beam 96 is at end 104 of the fiber 98 focused. Similarly, the light beam is also focused at the end 106 of the fiber 100, if the latter is located within the locations indicated by B in FIG. 5. The same also applies to the optical fiber 102, that is used to focus the light beam 96 at the end 108 of the fiber 102 at any point between the C in Fig. 5 is to be arranged marked positions »

Because of this caused by the concave surface 95 A fiber 90 can be focused using optical fibers of various sizes, such as those shown in FIG Fibers are coupled. A fiber with an even smaller diameter

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Therefore, the diameter of the fiber 98 must be positioned between the points A opposite the reflective surface. If the fiber 100 is arranged between the locations designated by B along the reflection beam path, can a fiber with a diameter similar to that of the optical fiber 90 can be coupled, with at most Little of the signal supplied from fiber 90 can be lost »Similarly, fibers with larger Diameter, e.g., the optical fiber 102 between the locations indicated by C in Figure 5 with respect to the reflective Component can be arranged, with a coupling between highly dissimilar optical fibers without significant Energy loss of the beam emerging from the fiber 90 becomes possible

A preferred embodiment of the reflective component is denoted by 120 in FIG. 7. The reflective component 120 contains a plastic body 122 with a concave surface 124 in the form of a ring band forms within the cylindrical body 122 of the reflective member 120. As best seen in FIG. 9, the cylindrical body 122 has a cylinder wall 128 and a circular end wall 130. The concave wall 126 is connected to the end wall 130 via a cylindrical flange 131. The reflective component 120 is attached to a shaft 132 which is connected to a motor 134. Therefore, when the reflective component 120 is rotated about the axis of the shaft 132, the radius of curvature of the reflective spherical surface is angularly displaced, whereby the angle of reflection is also changed .

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In Fig. 7 are in combination with the reflective component 120 several fibers 140, 142 and 144 shown. The optical fibers 140, 142 and 144 are in front of the foremost The edge of the reflective surface 124 is arranged in accordance with the illustration in FIGS. 7 and 8.

Note that in Figure 7, the light exits fiber 140 in the direction of line 146 and from the surface 124 of the reflective component 120 is reflected in the direction of the lines 48 and directed to the fiber 142. By excitement of the motor 134, the shaft 132 and the reflective member 120 become a predetermined amount. in the in Fig. 8 is rotated, whereby the beam 146 emerging from the optical fiber 140 along the lines 150 is reflected in the direction of the optical fiber 144. The axis about which shaft 132 rotates is related fixedly arranged on the fibers 140, 142 and 144.

The reflective component 120 can be equipped with a transparent component 122, the walls 128 and 130 are removed so that a lens is placed behind the reflective surface 124. The surface is 124 only partially mirrored, so that part of the material from the fiber 140 coming light can be branched off.

As best seen in Figure 9, fibers 140, 142 and 144 are each on the concave reflective surface 124 so that the axis of the fiber is in a plane perpendicular to the tangent of the reflective surface in whose center runs. For example, in FIG. 9, the dash-dotted line 152 represents the axis of the optical Represents fiber 142, and the fiber axis is directed to the concave surface 124 and is perpendicular to it tangent placed at the center of the concave surface 124

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As can be seen from the above description, the described optical coupling device facilitates the coupling between optical fiber ends without causing noticeable transmission losses, and it is possible, even Optically couple fibers of different diameters with one another using a reflective coupler.

In addition, the described optical coupling device has a particularly advantageous application in an optical one Relay switch with which the optical signal from a signal path can be switched to another »by using a reflective coupler in the relay switch the alignment of the axes between the fibers to be coupled can be effective for the transmission of signals from a to the other fiber to be maintained. Furthermore, the reflective coupler avoids repeated crashes and rubbing between the fiber ends to be coupled, since the only moving part of the relay switch is the reflective one Component is »

It should also be noted that the term "fiber" is used in its broadest sense as an optical waveguide and refers not only to individual fibers _s but also on fiber bundles. In other words, the coupler and relay switch can be applied to fiber bundles in the same way as has been described above with reference to individual fibers. Accordingly, the term fiber refers not only to individual fibers, but also to a bundle of fibers which carry the same signal.

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Claims (7)

PATENTANWÄLTE ZENZ & HELBER · O 43OO ESSEN 1 · AM RUHRSTEIN 1 ■ TEL .: (02O1) 4126 Page -J ^ - T 90 claims 1. Optical coupling device with at least two optical fibers, the ends of which can be optically coupled via the coupling device , characterized in that one end (36, 44, 48 $ 104, 106, 108) of the two fibers (22, 24, 26 ; 62, 64, 665 90, 98, 100, 102? 140, 142, 144) is directed onto a concave reflective surface (38 ";68;95; 124) of a reflective component (20; 60; 92; 120) and the concave reflective surface is so designed and arranged relative to the two fiber ends that an optical signal in one - (22; 62; 90; 140) of the two fibers is transmitted to the end (44, "48; 1O6 ₉ 108) of the other fiber is reflected and focused on this. 2 · Optical coupling device according to claim 1, characterized in that the reflective component (60) consists of light-permeable material and the reflective surface (68) is designed to be partially reflective, that on the side of the reflective component (60) facing away from the first fiber (62) a focusing element (76) and directed to the focusing element third fiber (80) are arranged, wherein the arrangement is such that a portion of the directed via the first fiber (62) on the reflecting member (60) signal to the second fiber (64) and another part of this signal is directed to the third fiber (80) 90 9 83 5 / Θ θ Z / ko. 3. Optical coupling device according to claim 1, characterized in that the reflective component (20) is movably mounted that in a first position (Fig. 1) of the reflective component the end (36) of the first fiber (22) over the reflective surface (38) with the end (44) of the second fiber (24) and in a second position (Fig. 2) of the reflective component (20) the end (36) of the first fiber (22) with the end (48) of a third Fiber (26) is coupled. _f 4. Optical coupling device according to one of claims 1 to 3, characterized in that the reflective Component (120) a spherical reflective surface (124) which is arranged rotatably about an axis of rotation (136), and that the axis of rotation (136) of the spherical reflective Surface (124) is arranged at a distance from the center of curvature of the spherical surface (124), so that rotation about the axis of rotation (136) causes rotation of the radius of curvature of the reflective surface (124). 5. Optical coupling device according to one of the claims 1 to 4, characterized in that the fibers (140, 142, 144) and the reflective surface (124) in a medium are arranged whose refractive index is equal to that of the fibers. 6. Optical coupling device according to one of claims 1 to 5, characterized in that the fibers (98, 100, 102) are arranged at a distance from the reflective surface (95) corresponding to their cross section. 7. Use of the optical coupling device according to one of claims 1 to 6 with a movably mounted reflective component (20; 60; 120) on which a beam reflecting and focusing surface (38; 68; 124) is designed as a relay switch for switching 909835/0604 23053-60 a signal emerging from a first fiber (22; 62; 140) between at least two further fibers (24, 26; 64, 66; 142, 144).