JPH06324239A - Optical cable with multiple wave light guides - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a configuration capable of sufficiently avoiding an excessive increase in attenuation due to a mechanical load of a wave light guide. The optical cable has a plurality of wave light guides, and the wave light guide has at least one predetermined structure.
It is provided in one group. Inside the structure ST1, a wave light guide U1 having different mechanical fragility
11 to U114; E112 to E133 are provided. Wave light guide U with smaller mechanical fragility
111-U134 are provided in a given structure ST1 in one or more regions of increased mechanical load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable having a plurality of wave light guides, the wave light guides being provided in at least one group having a predetermined structure (ST1). Wave light guides relate to types of optical cables that are subject to different mechanical loads inside the structure.

[0002]

BACKGROUND OF THE INVENTION It is known to manufacture optical cables with a significantly higher number of wave light guides, in which case the wave light guides are provided in groups as a predetermined structure. One possible configuration of a given structure of this kind is, in the case of so-called room cables, for example the arrangement of wave-guide strips inside a layered body. An example of this type of structure is shown in EP-A 1 492 206, in which the number of wave conductors is changed from the inside to the outside inside the strip strata forming one group in order to obtain a significantly higher packing density. It increases as you go.

In the case of a group of this kind, which has a defined structure, which is usually arranged to run spirally to the cable axis, the individual wave guides as such are:
It is not possible in any case to avoid mechanical loading, i.e. to position the wave guide in such a way that it bears only a slight load. This is because the wave guides are substantially mechanically coupled within the given structure at the aforementioned positions. This type of mechanical load (micro-
(Also known as macrobending) causes a substantially undesirably strong increase in damping.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a construction which, while maintaining a given structure, avoids too much attenuation increase due to the mechanical loading of the wave guide as far as possible.

[0005]

This problem has been solved as follows: a wave light guide having different mechanical fragility is provided inside the structure,
Wave light guides with less mechanical fragility appear for a given structure, with increased mechanical loading 1.
It is provided in one or more areas.

[0006]

In the case of the known predetermined structures (for example in the case of strip laminates in room cables), the same type of wave guide is always used inside the structure, ie a laminate of this kind. The present invention, on the other hand, starts from this principle of a homogeneous wave light guide inside the structure. In this case, in the present invention, wave light guides having different fragility are used as follows. That is to say, where there is a significant mechanical load, first of all, a wave guide is provided which is designed for increased mechanical load (eg micro-bending), ie is less susceptible to mechanical load. Used.
In other areas inside the structure, wave light guides with higher fragility to mechanical loads can be used. This is because here the mechanical loading of the wave guide, and thus the attenuation increase, is essentially smaller or does not occur at all. Waveguides that are mechanically less susceptible to breakage typically have higher transmission attenuation.
This slight increase in transmission attenuation is orders of magnitude less than the increase in attenuation due to too much mechanical load in the case of wave conductors that are susceptible to mechanical loading.

Various configurations of the invention are set forth in claims 2 and below.

Next, an embodiment of the present invention will be described with reference to the drawings.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENT The optical cable shown in FIG. 1 has in its center a tensile-resistant element CE1. On this element is provided an extruded plastic layer CP1 of, for example, polyethylene. A chamber element C having a substantially U-shaped cross section is formed on the plastic layer CP1.
A11 and CA1n are shown. During the stranding process, these chamber elements CA11 to CA1n are connected to the support CP1.
It is linearized by running in a spiral on the top of. Of course, in the completed cable, the exterior MA1 and the support CP
The total interior space between 1 and n is n such chamber elements CA1-C.
Filled with An. Exterior MA1 is provided on the outside. Within each chamber element is a group of wave light guides (as shown in CA11) provided in a predetermined structure. In the case of the chamber element CA11 in this example, the structure ST1 is composed of layered bodies B11, B12, B13 of wave light guide strips each containing four wave light guides. Each of the predetermined structures ST1 forms a rectangular shape as a connection line for the wave light guide located outside.

As a result of stranding the chamber element CA11 onto the support CP1, the wave light guide is subjected to different loads inside the structure ST. In this case, substantially the following loads occur: torsional loads due to winding along the twisted axis (center point of CE1) and bending loads due to the bent guidance of the spiral path. These loads increase as the radial extension and / or circumferential extension of the structure ST1 including the wave light guide increases. In this case, a special load is applied to the wave light guide located on the outermost side, because this wave light guide exists at almost the intersection of the diagonal lines of the structure ST1 both with respect to twisting and bending (virtual) from the neutral axis AX1. Because they are far apart.

Larger mechanical loads on the wave guide (above a certain tolerance limit) result in a significant increase in the transmission attenuation of the wave guide. For the purpose of avoiding this kind of degradation of the wave light guide in specially loaded partial areas, for example in the outermost left and right corners of the structure ST1, the mechanical breakage, here designated as a black dot, is shown. Non-trivial wave light guides U111 and U114 are provided. In this way, too much attenuation increase due to the twisting process or as a result of the microrefractive effect is substantially reduced.

Similarly, as the optical waveguide body subjected to the increased mechanical load, the lowermost strip B13 of the laminated body ST1 is formed.
Both outermost optical waveguides U131 and U134 are also of interest. Therefore, in this case as well, a wave guide having a mechanically sensitive load that is significantly reduced is provided. On the other hand, the wave light guide strip B13 existing on the innermost side of both
Wave light guides E132 and E133 of the structure ST1
Since it is closer to the neutral axis, it is mechanically less loaded. As such, their damping due to mechanical loading is not substantially increased (eg during the stranding process).

Wave light guides which should have less fragility inside the structure, eg U111-U1
The choice of 34 depends on the cable structure and the respective parameters of the stranding process. In this case, the length of one section that linearizes each structure is such that an increased mechanical load is generated when the length of one section becomes shorter,
It is processed. Furthermore, the outer diameter of each structure is
As the structure gets larger (ie the number of wave guides inside the structure increases), the mechanical loading of the individual wave guides in the outer region is also increased. How many of the optical waveguides inside one structure should be provided as wave conductors that are not mechanically fragile, such as U111-U134, depends on the given conditions and the arrangement characteristics inherent in each structure. Dependent. In addition to theoretical considerations in each case, the number and position of the respectively specially mechanically loaded wave light guides inside the structure can also be easily determined by practical trials as follows. That is, in one cable embodiment, it is determined, for example, by measuring a wave guide that suffers an increase in attenuation above an acceptable limit as a result of the twisting process.

To clarify the above description, FIG. 2 is used. The optical cable OC2 shown here is the exterior MA
2, with a tensile strength element and a plastic coating CP2 mounted on it. The structure ST2 consists of three different wave guide strips B21, B22 and B23 for the purpose of obtaining a significantly higher transmission capacity. When viewed from the outside to the inside of these strips, each includes an increasing number of wave light guides. The entire inner chamber of the cable core is filled with a certain number of such structures. In the case of the present invention, for the sake of simplicity of the drawing, only the structure ST2 in which the chamber element is contained in CA21 is shown, while the other three similarly formed structures are only shown in outline. ing.

The outermost wave light guide strip B21 is 8
Including one wave light guide. The three wave light guides U211, U212 and 213 and U216, U217 and U218 respectively located on the left- and right-hand outer sides are subjected to special mechanical loads and thus have an inner structure which makes them insensitive to mechanical loads. . On the other hand, the wave guides E214 and E215 provided near the center are not so far apart from the neutral axis AX2 of the structure ST2, and therefore receive only a mechanically smaller load. Therefore E
For 214 and E215, it is not necessary to use wave light guides, which are characterized by a particularly small sensitive load with respect to their mechanical properties.

In the case of a second wave conductor strip B22 having a total of six wave conductors, both outer left and right wave conductors U221, U222 and U22, respectively.
5, U226 is embodied as a wave conductor with a significantly smaller sensitivity. On the other hand, both inner wave light guides EP223 and E224, which are located closer to the neutral axis AX2, can have greater fragility with respect to mechanical loading.

In the lowermost wave light guide strip LB23 having a total of four wave light guides, the wave light guides U231 and U234 located on both outer sides are provided as wave light guides which are not easily mechanically damaged. On the other hand, the inner wave guides E232 and E233 may have greater fragility to mechanical loads. Because E232 and E233 are the neutral axis AX2
Because it is located closer to.

As shown in this embodiment of FIGS. 1 and 2, inside the structure, the number and division of the wave light guides U111 to U234, which are not mechanically fragile, is:
It can be selected according to the mechanical fragility that is uniquely generated in each structure ST1 or ST2. In this case, a wave guide is used that is mechanically less prone to breakage when the distance from the neutral axis AX1 or AX2 increases. On the other hand, in the core region, the neutral axes AX1 to AX1
Waveguides E112 to E223 are provided which have a greater mechanical fragility with respect to their damping properties against mechanical loads, centered around X2.

In the case of the arrangement according to FIG. 3, the optical cable OC3
In, there is provided a larger plastic body CP3 with approximately rectangular chambers CA31 to CA3n around the central tensile strength core CE3. On top of this CP3—if necessary, underneath a cover (not shown here) and underneath the intermediate layer—the exterior MA3 is provided. Rectangular notches CA31 to C running in a helical shape
In A3n, a structure containing a wave light guide is provided, for example in the form of a strip laminate. In the case of this embodiment, only one structure ST3 is shown. Its structure and elements are corresponding to those of FIG. 1, that is to say four wave conductors U311 to U334 arranged at each corner are provided, which are not particularly susceptible to mechanical loads.

FIG. 4 shows a twisted element OE. It has an outer protective sleeve SH, in which is housed a structure ST4 of a total of 16 wave light guides. These 16 wave light guides are each divided into four wave light guide strips B41-B44. Wave light guides U411, U414, U441 and U respectively arranged at the corners.
444 is formed as a wave light guide that is not particularly susceptible to mechanical loading. On the other hand, the wave light guides-located closer to the neutral axis AX4 of the structure ST4-shown as white circles lying further inside-have greater mechanical fragility.

The susceptibility of the fiber to microbending is described in publications such as Bell "System. Tech.
Journal 55, 1976, pages 937-955. Its fragility is measured in publications such as Bell "System.Tech.Journal.
55, 1976, pages 937-955.
For example, the measurement is performed by "International W
ire and Cable Symposium ”
(IWCS) Proceedings 1989, 45th
The so-called "mesh wire t" shown on page 0
est ". Micro-bending fragility of a fiber or wave light guide can be measured, for example, by IWCS, Proc.
It can be characterized by the MAC value shown in eedings 1989, pages 704-709. Next, the MAC value is used for explaining related matters.

The following equation applies:

MAC = MFD / λ _ceff As shown in this equation, the mode field diameter MF
As D is made smaller, bending _fragility is reduced (λ _ceff = effective limit wavelength). A light guiding fiber having a first index of refraction for the core region and a second predetermined index of refraction for the exterior region has a MAC value which is typically about 7.5. Reducing this MAC value of 7.5, for example to 6.5 (e.g. by reducing the mode field diameter MFD) reduces the microbend fragility by a factor greater than 2. As a result, this type of wave light guide is subject to increased mechanical loading. In this case, this does not result in an undesirably large increase in attenuation. Lower M
Wave light guides of this kind having an AC value (ie for example below 7.4, preferably below 7.0, and even better below 6.5) are wave guides U111 to U444 of FIGS. Is perfect for. Easy to break wave light guide (E112-E22
Wave light guide (U111)
The difference from the MAC value of ~ U444) should preferably be 0.2, for example greater than 0.5 and optimally greater than 1.0. The above value is λ = 130
It is related to 0 nm.

The design of the light guiding fibers can be modified accordingly in order to obtain the desired non-fragility of the wave light guide. For example, increasing the difference between the index of refraction of the core of the light guiding fiber and the index of refraction of the sheath improves the guiding properties of the fiber and thus makes it less susceptible to bending. This kind of improvement in the mechanical brazing properties of the optical fiber, of course, usually results in a slight increase in attenuation, but this increase is due to the attenuation of the mechanically fragile light-guiding fiber when the mechanical load is increased. It is significantly smaller than the degree increase.

Next, the derivation of the relational expression for explaining the above-mentioned phenomenon will be briefly described.

FIG. 5 shows that the micro-refractive loss α depends on the MAC value and is a = 4 to 4.3 μm (a = core radius) and Δ.
(Difference in normalized refractive index) = 0.0033-0.00
It is shown for 39% (n ₁ = refractive index of the core of the wave light guide, n ₂ = exterior refractive index).

Δ = (n ² (1) −n ² (2)) / 2n ² (1) (2) V-parameter: (structure parameter) V = (2π / λ) α · n ₁ · √2Δ ( 3) Mode field diameter

[0028]

[Equation 1]

Attenuation due to Rayleigh scattering α _S = (0.685 + 66Δn) / λ ⁴ (5) Start with the following values for the following refractive indices: Vc = 2.405 λc = λ _ceff +100 nm (λc = theoretical N ₁ = 1.451; where λ = 1300 nm (1) to (4), the following formula is obtained.

Δ = (1 / 2π ² ) (λcVc / MAC ·
λ _ceff · n ₁ ) ... 0.65 + 1.619 / (λ cVc /
λ) · + · 2.879 / (λcVc / λ) The normalized refractive index difference Δ is converted into a refractive index difference Δn, and the result is substituted into (5), as shown in FIG. λ
The dependence of the damping α _s as a function of _ceff on various MACs
Obtained for value. The curve K1 applies to the case of MAC = 6.5, the curve K2 applies to the case of MAC = 7, and the curve K3 applies to the case of MAC = 7.5.

As shown in FIG. 6, the kilometer attenuation (at 1300 nm) is still less than 0.4 dB / km even for MAC = 6.5. Compared with the attenuation value when MAC = 7.5, the attenuation is only about 5 · 10 to ² dB.
/ Km only increases. However, the micro-refraction fragility is significantly reduced.

A fiber of this kind is therefore suitable, for example, at the location of the cable structure, where the fiber is subject to a significantly higher microrefraction.

FIG. 7 shows the upper, middle and lower wave light composed of a strip laminate with 10 fiber strips provided in the cable of the U-profile shown in FIG. The attenuation value α of the conductors L1 to L12 is shown.

The broken line shows the attenuation value of the fiber band when no load is applied. That is, all wave light guides L1
-L12 has about the same attenuation of 0.2 dB / km at a wavelength of 1550 nm. The use of fragile fibers in bending significantly increases the attenuation for both wave conductors on the outermost side of the outer strip in the case of the aforementioned loads, for example in the case of strandedness itself or in the internal temperature test of the cable, which results in a white circle. EL1 and EL12
Is at the value indicated by. That is, attenuation increase is about 1.0
It has a value of dB / km. In this case, the MAC value 8.2 is defined. On the other hand, the MAC that is not susceptible to bending due to both outermost wave guides L1 and L12
When a fiber with a value of 6.8 is used, the attenuation increase in both outer wave guides is significantly smaller, at the point UL1.
(About 0.33 dB / km) and point UL12 (about 0.45 d
Only the value indicated by B / km) is reached.

Therefore, by using a wave guide according to the invention, which is less susceptible to bending in the critical region of the structure, a significant improvement in the overall properties of the structure is achieved. In particular, the following improvements are made: An overall lower damping value is obtained with the maintenance of this structure.

For a given damping value, disadvantageous processing parameters (larger bends, smaller section lengths) can be tolerated.

If the processing parameters and attenuation do not change, a larger number of wave light guides can be installed inside the structure.

A layered structure of eight wave light guides inside one strip, rather than only six wave light guides inside one strip inside one layered product, exceeds the allowable error value. It can be realized without crossing.

It is also possible to construct, within a given structure, all wave light guides which have only a slight fragility, ie a MAC value of 7.4, preferably 7.
It is also possible to configure all wave light guides with MAC values below 0, even as low as 6.5.

The actual given conditions, such as the dimensioning to be maintained, are always taken into account when constructing the structure with wave light guides which are mechanically slightly fragile in the most heavily loaded areas inside the structure. You don't have to. Another object of the present invention is therefore to provide a means for the simple construction of a given structure with wave conductors of different mechanical fragility, with due consideration of the actual conditions given. Is. This problem is solved by the first solving means of this modified embodiment as follows. That is, a wave guide in the region of higher mechanical loading has been solved by making its primary coating layer thicker than the wave guide in the region of lower mechanical loading.

First coating sleeve (primary coating) of the wave light guide in the region of higher mechanical load respectively
Little increase in the thickness of the wave-guide, which is subject to these micro- and / or macro-bends (so-called "micro- or macro-bending"), which can lead to unacceptably high attenuation increases in the transmission properties of the wave guide. Like This is because an increase in the thickness of the primary coating advantageously provides an additional damping effect, for example on the mechanical loads that can occur, for example compressive loads. In addition, this type of wave light guide allows various deformable structural configurations which are adapted to the practically given conditions in a very simple manner. This is because by adjusting the thickness of the primary coating of each wave light guide as expected, for example, the predetermined space condition of the structure, the value selection data, the maximum allowable compressive force to each wave light guide, etc. This is because it can be considered extremely easily and advantageously when constructing the structure.

According to the second solving means of the modified embodiment, the above-mentioned problems are solved as follows. That is to say that the wave guide in each region of higher mechanical load is solved by having a softer material for its first coating than the wave guide in the region of lower mechanical load.

With this advantageous configuration, unacceptably high transmission attenuation is avoided even for wave light guides at higher mechanical loads inside the structure. For the same outer diameter, a more strongly loaded wave light guide with a softer material for the primary coating will be better cushioned, ie mechanically, than a light load wave light guide. Attenuated. In this way, an optimized structure configuration adapted to various given conditions is possible.

Due to the primary coating of the wave light guide, which is more strongly loaded, a larger primary coating thickness (primary coating) than for the primary coating of the wave light guide, which is mechanically lightly loaded. ) As well as at the same time providing a softer material. This combined configuration makes it significantly easier for a structure to meet various given conditions, such as value selection data, mechanical minimum load (brazing resistance), permissible pass attenuation for each individual wave light guide, etc. Composed.

When a load is generated, the belt-shaped laminated body ST of FIG.
1 is substantially supported by four fibers U111, U114, U131, U134 at the corners of the chamber space. For the purpose of increasing the damping of this type of corner, for example, temperature cycling, bending- or lateral pressure tests can be carried out, i.e. the corner fibers in the stratification being the most fragile.

The desired fragility of the wave guides of the structure-for example in their four corner regions-is obtained as follows: the design of the coating of the light guiding fiber at the higher mechanical load points. The (coating design) is obtained by being deformed compared to that of the light guiding fiber in the region of lower mechanical loading. FIG. 12 shows the structure of the wave light guide LW1 *.
This is, for example, the wave conductors U111 to U1 which are mechanically slightly fragile in the structure ST1 of FIG.
Can be used for 34. The wave light guide LW1 * of FIG. 12 has a light guiding glass core CO in the center. The CO is surrounded by an exterior glass (“coating”) CL. as a result,
A light guiding fiber having an outer diameter DF is formed.
At least one primary inner plastic coating PC is applied on the light guiding fiber. A soft material such as urethane acrylate having an elastic modulus of 0.5 to 2.5 MPa is selected for this primary coating PC. This one
The next coating PC further comprises at least one secondary,
Further, it is covered by a coating (secondary coating) provided on the outside. Due to this secondary coating SC a harder material than that for the primary coating, eg SC, urethane acrylate or silicon acrylate epoxy dacrylate-modulus of elasticity 500-1500 MPa-substantially damages the outer surface of the primary coating PC. It is selected with the aim of avoiding this, and also with the aim of enabling a reliable problem-free subsequent treatment of the light guiding fiber.

For the purpose of making the wave guides at higher mechanical loads, such as U111 to U134 of FIG. 1, mechanically less sensitive to the pressures available within the structure ST1 of the wave guides. The coating is formed as follows. That is, the coatings are formed to each have a primary coating with a greater layer thickness than the wave light guide at low mechanical load locations, such as E112 to E133. The basis is "Inte
national wire und cable
Symposium Proceedings "(IW
CS), 1993, pp. 389-390, primarily because the primary coating PC affects the microbend fragility of the wave light guide. Wave light guide U111, for example in the region of higher mechanical pressure loading
In the region of mechanical loading where U134 is smaller than the wave light guide such as E112 to E133 in FIG.
1.5 to 4 times, for example, 2 to 3 times larger, part 1
Subsequent coating has a layer thickness of PC. Due to the primary coating PC of the wave conductor, which is preferably less mechanically fragile, the layer thickness is from 20 to 50 μm, for example 3
0 to 40 μm is selected. For example, increasing the thickness of the soft primary coating PC increases its cushioning or buffering effect. As a result, the pressure load on each light guiding fiber that may act is damped, forming an overall stiffer wave light guide.

FIG. 1 provided with a primary coating PC.
The light guide fiber of the second wave light guide LW1 * is, for example, 1.1 to 1.5 times, for example, 1.2 to 1.5 times, as compared with the mechanically fragile wave light guide such as E112 to E133 in FIG.
It has an outer diameter DPC that is 1.4 times larger. For example, outer diameter DPC
Is selected to be 165 to 250 μm, for example 170 to 210 μm. Secondary coating SC in case of wave light guides U111 to U134 of FIG. 1 with smaller mechanical fragility
Is a wave light guide E112 of FIG.
Each has a layer thickness that is approximately equal or 1.1 to 2 times greater as compared to the E133 secondary coating.
The layer thickness for the secondary coating SC is preferably 10
-40 μm, for example 20-30 μm. Therefore, the wave light guide LW is mechanically resistant to the compressive load.
1 * is a wave light guide E112 of FIG.
~ 1.2 to 1.8 times more than E133, for example 1.2 to
It has a 1.5 times larger overall outer diameter. For example, the entire outer diameter DLW is 200 to 300 μm, for example 200 to 250 μm.
Selected as m.

In order to explain the influence of the primary coating PC on the microbend fragility of the respective wave guides, the following table shows, for example, five different coating types T1 to T5 of the wave guides.

These are, for example, "Internatio"
nal Wire und Cable Symposs
ium (IWCS) Proceedings, 198
9. Subject to the so-called "mesh wire test", shown on page 450. Each light guide type T1 ~ T
5, individually to the overall outer diameter DLW, the light guiding fiber diameter DF, the outer diameter DPC, the light guiding fiber coated with the primary coating PC, and their belonging to the primary coating PC and the secondary coating SC. The elastic modulus of is shown.

Table 1 Elastic Modulus of DLW DPC DF Coated PC SC [μm] [μm] [μm] Model [MPa] [MPa] 180 150 125 T1 1.6 1530 200 150 125 T2 1.6 1530 200 165 125 T3 1.6 1530 245 205 125 T4 2.6 690 245 190 125 T5 1.6 580 In FIG. 13, for example, for five different coated wave conductors T1 to T5, respectively, the micro bending loss (attenuation loss) α * dB / kg compressive load is so-called M.
Depending on the AC value, it is shown over the MAC region, eg 6.5-8.5, at a wavelength of 1550 nm. MA
C value is IWCS, Proceedings 1988,
As shown on pages 704-709, characterize the micro-fragility of the fiber or wave guide.
Next, the MAC value is used for explaining related matters. In this case, the following formula applies: MAC = MFD / λ _ceff As shown in this formula, as the mode field diameter MFD of each wave guide decreases, the susceptibility to bending decreases. The measured straight line for the coating type T1 of Table 1, indicated by T1 * in FIG. 13, shows the attenuation ratio based on the micro bending loss in the case of the current monomode wave light guide, depending on the MAC value. Secondary coating type T2 compared to this primary coating type T1
, The secondary coating is increased by about 20 μm. This gives rise to a measuring line T2 * which is slightly below the measuring line T1 in the damping diagram of FIG. On the other hand, a significantly greater reduction or reduction of the transmission attenuation is achieved by increasing the thickness of the primary coating layer.
This means, for example, that the coating type T3-its measuring line T3 * runs below and in parallel to the measuring line T2 * at intervals of approximately 0.05 dB / kg (one measuring unit). FIG. 13 further shows the measurement line T4 * for the coating type of Table 1. This straight line runs significantly below the measurement curve T3 * and runs at a smaller slope than T3 *. The coating type T4 has a larger layer thickness (DP) than the coating type T3.
C-DF = 80 μm). At the same time, in the case of the secondary coating PC, a material with a smaller elastic modulus, for example less than half, is selected in this embodiment. In the case of this coating T4 design, a further reduction of the damping losses is achieved. This is shown in the 6.5-8.5 MAC region in question by the measuring straight line T4 * running with a smaller slope than the measuring curve T3 *. In the case of coating type T5, finally the wave light guide can be made to be approximately independent of the outer compressive load in the MAC value range 6.5-8.5. This means, for example, that the elastic coefficient of the primary coating PC is T4.
It is achieved by reducing the elastic modulus of the.
This is shown in the measuring curve T5 * which runs under T4 * in an approximately constant manner.

In the case of a wave light guide which is located at a point of higher mechanical load, for example a pressing force, additionally or not dependent on an increase in the thickness of the layer of the primary coating, eg FIG. In case of U111 to U134 of
These are made more pressure sensitive, ie, more brazing, if desired, by: That is 1
Structure ST of FIG. 1 for the next coating PC
The selection of softer materials makes it more susceptible to pressure, ie more robust, than the wave light guides in the smaller mechanical load range within 1, such as the PC of E112 to E133. . Therefore, it is advantageous that the wave guide in the region of higher mechanical loading, such as U111 to U134 of FIG. 1, has a modulus of elasticity which is as low as possible than that of the wave guide in the region of lower mechanical loading. For example, because of the primary coating PC of the strongly loaded wave light guide of FIG. 1, FIG.
1 to more than the materials for the wave light guides E112 to E133
A material is selected that is 5 times softer, for example 1 to 2.5 times softer. Particularly strongly loaded wave light guide U of FIG.
For the primary coatings 111 to U134, a modulus of elasticity is chosen which is, for example, 1 to 2.5 times smaller than the modulus of elasticity for the wave guide in the region of smaller loading. Preferably, the more robust light guides U111-U of FIG.
134 has an elastic modulus of 0.5-3, for example 1-2 MPa. In addition or without depending on this configuration, the wave guide in the region of higher pressure load can be made more sensitive to pressure if desired in the following way. That is, by selecting a softer material for the secondary coating than the material of the light guide which bears a smaller load, it can be made more sensitive to pressure. Advantageously even more robust wave light guides U111 to U134-2
The modulus of elasticity for the subsequent coating is chosen to be 1.0 to 2.5 times, for example 1.0 to 2.0 times larger than the modulus of elasticity for the wave conductors E112 to E113 which are mechanically more fragile. Secondary coatings for wave light guides U111 to U134, which are mechanically more stable to pressure, for example, have a modulus of elasticity of 500 to 1600 MPa, for example 8
It has 00 to 1500 MPa. The secondary coating therefore advantageously acts as a protective layer. Therefore, the external force is 2
It can be transferred from the next coating SC to the surface of the inner coating (primary coating) PC.

Therefore, the influence of the elastic modulus of the secondary coating is substantially negligible as compared with the influence of the primary coating.

For this reason, the wave conductors having the coating types T3 to T5 in Table 1 are customarily valued to correspond to the coating type T1 in the MAC value range of approximately 6.5 to 8.5. It has a smaller microbending loss than. Therefore, a modified wave light guide of this kind is located at the location of the structure ST1 in FIG. 1 where the possible pressing forces act. In the embodiment of FIG. 1, this position is, for example, the position of the four corners of the strip laminated body. But especially surely all strips B
In the case of 11, B12 and B13, it is also possible to provide a pressure-sensitive wave light guide of this kind at the corners in the strip laminate of FIG.

FIG. 8 shows a wave light guide strip BL1 as a basic unit of the structure ST1 of FIG. This strip BL1 occupies only the position of B13 located at the bottom of FIG. 1 and / or the location of the strip B11 located at the top of the stack of layers (structure ST1) of FIG. On the other hand, the other strips mounted in the middle can be strips of conventional design, each with a wave guide of the same kind. However, as an alternative to this, in the layered body ST1 of FIG.
, That is, the same format. This alternative form is
It has the advantage that an integral multiple splice device can be used.

The strip BL1 consists of a substantially rectangular elongated plastic outer jacket AH1 and a wave conductor standard strip GB each having at least one further additional wave conductor LW1 *, LWn *. The latter are respectively abutted separately on the outer short side of the standard strip GB on the outer side in the longitudinal direction by means of the connecting means VM to the jacket AH1. Therefore, the n wave guides LW1 to LWn are embedded in the outer cover AH1 of the standard strip GB and are laterally defined by two separate wave guides LW1 * and LWn *, and as a result, they are smaller than the standard strip GB. A wide strip BL1 is formed. In this case, the wave light guides LW1 to LWn are housed in the center of the jacket AH1 along the virtual linear connection line.
On the other hand, both wave conductors LW1 *, LWn * follow on both sides of this virtual connecting line without an outer protective coating. The separate additional wave conductors LW1 *, LWn * are shown in FIG. 8 with a larger diameter than the wave conductors LW1 to LWn of the standard strip GB. This means the following. That is, as shown in FIG. 8, wave light guides LW1 * and LWn * are provided as described above, for example, for the wave light guides U111 to U134. Advantageously, both of these wave conductors LW1 *, LWn * have a layer thickness of their primary coating which is greater than that of the wave conductors LW1 to LWn which, due to their inner position, are subject to a small compressive load (eg the coating of Table 1). Wave light guide corresponding to type T3).
Of course, all the other wave guide types mentioned above (different refractive indices for the core and sheath period, ie different MAC values) and wave guides LW1 *, LWn *, which are less susceptible to possible pressure forces, for example preferably coatings of Table 1. Coating designs for wave light guides corresponding to types T3, T4, T5 can also be used. Wave light guide LW1
As the connection means VM for *, LWn *, for example, an adhesive, a conventional strip coating or other adhesive means can be selected.

In FIG. 8, the wave conductors LW1 *, LWn * defining the standard strip GB on the side face act in the form of side edge protection for the wave conductors LW1 to LWn located inside.
Therefore, these are exactly at the locations inside the strip BL1 where the pressing force that can be generated is the strongest, that is, the strip BL.
It is provided at one end. In the band BL1 of FIG. 1, the wave light guides LW1 *, LW provided on both outermost sides
Nonetheless, only n * each has its primary coating envelope, and as a whole, nevertheless, is almost the same strip as a standard strip with n + 2 similar wave light guides inside the envelope AH1. Quantity is maintained. In this way, a very compact strip BL1 having two different types of wave light guides is formed. Small pressure-stable wave light guides LW1 to LWn in the inner region defined by the jacket AH1 and at least two pressures opposite them in the outer region of the narrow side of the standard strip GB, which bear the possible loads. More stable wave light guide LW
1 *, LWn *. This strip BL1 is therefore characterized by a significantly higher aggregate density as well as by a significantly simpler production. Furthermore, a uniform fiber position in the strip is advantageously allowed during manufacturing.

In the case of the wave light guide strip BL2 of FIG. 9, FIG.
The difference from the strip BL1 is that both the wave light guides LW1 and LW
Wn * is integrated on one side in each corner position of the short side of the jacket AH1. Wave light guide LW1 *, L
The outer contour of W2 * forms the rounded short side for the strip BL2. (Parts directly taken from FIG. 8 are designated with the same reference symbols in FIG. 9). The wave light guides LW1 *, LW2 * have an outer diameter corresponding to the thickness of the strip. The wave guide therefore forms a kind of closure for the short side of the envelope AH1.

In place of the strip BL2 of FIG. 9, both wave conductors LW1 *, LWn * in FIG. 10 are completely covered by AH.
Are integrated into two, i.e. they are in common with the wave guides L1 to Ln completely embedded in the plastic material of the jacket. In this way, its envelope AH3
The wave light guide strip BL3 is formed substantially uniformly with respect to. This is because the fibers at the corners are also surrounded by this protective jacket.

Finally, FIG. 11 shows the strips B11 to B of FIG.
13 as well as additional or independent configurations for BL1 to BL3 of FIGS. 8 to 10: each wave conductor strip is surrounded by an additional additional strip coating. In FIG. 11, for example, the strip B shown in FIG.
L1 is completely surrounded by another strip coating BC. In this case, the strip BL1 is shown only as a substantially rectangular block for simplicity. The strip coating and the diagonal lines of the strip BL1 are also omitted for clarity. As an additional strip coating, for example, 1 to more than the strip AH1 already provided.
A material is selected that has a modulus of elasticity that is five times smaller. Preferably this additional strip coating has a modulus of elasticity of 50-5.
It has 00 N / mm.

Therefore, another strip coating BC is
Form an additional soft-or buffer-layer around the entire band BL1. If necessary, a lubricant additive
It can be provided between the additional strip coating BC and the jacket of the strip BL1 or in the additional strip coating itself. The purpose is to reduce the stress between the strips of the layered body. The load in the laminate is therefore advantageously reduced by offsetting the local over / under-length in the cable (cable when bent). FIG. 11 shows a two-layer strip. The additional strip coating layer BC of this strip has the effect of additionally damping the compressive load. For example, the layer thickness of this additional strip coating BC is between 10 and 40 μm, for example selected between 20 and 320 μm. The following value selections are indeed suitable: a) The outer diameter of the wave light guides LW1 *, LW2 * is 0.245.
~ 0.300 mm; b) The outer diameter of the wave light guides LB1 to LBn is 0.180 to.
0.245 mm; c) The overall thickness of the strip (including the additional coating BC) λ (overall height) is between 0.245 and 032.
mm.

FIG. 14 shows the damping ratio in the case of a rectangular strip laminated body consisting of 16 upper and lower layered strips of the same model according to the present invention shown in FIGS. 1 to 13, for example. This is compared to a conventional 16-tier strip laminate consisting of upper and lower layered strips with respective wave light guides of equal magnitude to mechanical compression forces. In the diagram of FIG. 14, the measured relative attenuation values α (db / km) are shown respectively for the first, both central (ie 8th and 9th) and lowermost and uppermost waveguide bands. Shown for the last fiber position in the body. In this case, the relative measurement value in the case of the strip body located at the top in the strip body stratified body constituted by the present invention, the relative measurement value for the strip body located at the bottom is indicated by the respective written rectangles. It is shown by an unfilled empty square. The relative measurement values for the wave conductor of the strip located at the top of the conventional strip laminate are indicated by the circles marked, as well as the measurements for the strip at the bottom thereof are empty. It is shown by a circle without. The attenuation measurements at the corners of the strip stratification according to the invention are namely the attenuation measurements at the 1st and 16th fiber positions of the strip located at the top and the bottom.
Relative attenuation measurement value of the wave light guide at the corner position of the strip laminated body configured as in the past (α = 8.9; α = 4.
0; α = 6.2; α = 5.3). In the case of the strips located at least at the top and at the bottom, respectively, a wave light conductor is provided, respectively, at least at the corner positions of the strip body stratification, the wave light conductor having a strip body stratification structure. Is less sensitive to possible compressive forces than in areas where there is little load applied. With this configuration, it is possible to significantly reduce the transmission attenuation of the wave light guide at the corner positions of the strip laminated body. For the same cable diameter, the damping increase is reduced by a factor of 2 to 12 compared to the strip laminate with the standard strip. Further, FIG.
Of the attenuation diagram for a wave light guide at an intermediate fiber position, for example the 8th and 9th fibers in the respective strips for the strips according to the invention and for the conventional strips. It is clearly shown to have approximately equal transmission attenuation due to the wave light guide in position. This local fiber position is maintained inside the structure without microbending. 1 to 11, for example, the configuration according to the invention of a strip laminate having the basic structure shown in FIGS. 8 to 11, also for the wave light guide at the corner positions of the strip laminate of FIG. 0.3 dB when λ = 1550 nm
Damping measurements below / km are obtained. The intermediate fiber position in each strip can be occupied by a wave light guide with a greater microbend sensitivity. Because they are subject to very little compressive forces that can occur.

A structure which is extremely resistant to the possible pressing forces is obtained in the following cases. That is, it is obtained when the entire wave light guide strip of the layered structure ST1 of FIG. 1 is replaced by a wave light guide of the same kind, by the strips of the same embodiment of FIGS. 1 to 11, for example FIGS. 8 to 1. The wave conductor, which is mechanically insensitive, therefore lies on the outer side of the imaginary rectangle-which encloses the other wave conductors located on the inside in a region of little load.

Bands of this kind, which are constructed as shown in FIGS. 1 to 11 for example FIGS. 8 to 11, are suitable for a wide variety of applications in wave conductor technology, for example indoor cables (FIG. 3). ) Suitable for installation in chambers of U-profile cables (Fig. 1) or bundle cables (Fig. 4).

[Brief description of drawings]

1 is a cross-sectional view of a first optical cable according to the present invention.

2 shows a variant of the embodiment according to FIG.

FIG. 3 is a modification of the embodiment according to FIG.

FIG. 4 is a modification of the embodiment according to FIG.

FIG. 5 is a diagram showing a relationship between a MAC value and an increase in attenuation due to micro bending loss.

FIG. 6 is a diagram showing attenuation loss in the case of different MAC values depending on a limit wavelength.

FIG. 7 shows the upper, middle and lower strips of the strip laminate.

FIG. 8 shows a first wave light guide in the case of an optical cable according to FIG.
It is a cross-sectional view of the basic structure of.

9 is a first modification of the basic structure of FIG.

10 is a second modification of the basic structure of FIG.

11 shows another basic structure of a wave light guide for the optical cable shown in FIG.

12 for a structure according to FIGS. 1 to 11,
It is a block diagram of the wave light guide which has almost no mechanical load.

FIG. 13 is a diagram showing the relationship between the MAC value and the increase in attenuation due to microbending in wave light guides having coating layers of different thicknesses.

FIG. 14 is an attenuation diagram of an upper, middle, and lower wave light guide-wave light guide in a strip in the optical cable having the basic structure according to FIGS. 1 to 11.

[Explanation of symbols]

 OC1 optical cable CA11 to CA1n chamber element CE1, CE2 pull resistance element CP1 support ST1, ST4 structure U111 to U114, E112 to E133 wave light conductors AX1, AX2, AX4 neutral axis MA1, MA3 jacket U411, U414, U441, U444 optical Wave Body B41 to B44 Optical Waveguide Band CA31 to CA3n Notch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Waldemar Steckline Coburg am Seessternt 13 Ar (72) Inventor Clemens Unger Redental Schlossgarten 3 (72) Inventor Ernst Opel Schwarz, Federal Republic of Germany Zenbach an der saale velkenreut 12

Claims (28)

[Claims] 1. An optical cable having a plurality of wave light guides, wherein the wave light guides have a predetermined structure (ST1).
In the optical cable of the type in which the individual wave light guides are subjected to different mechanical loads inside the structure (ST1), the individual wave light guides have different mechanical loads inside the structure (ST1). Wave light guide with fragility (U111-U114; E
112-E133) are provided and have a smaller mechanical fragility (U111-U13).
An optical cable with a plurality of wave light guides, characterized in that 4) is provided in one or more regions of a given structure (ST1) in which an increased mechanical load appears. 2. A wave light guide (U1) having a smaller mechanical fragility inside the structure (ST1).
11. The optical cable according to claim 1, wherein 11, U112) is provided at a location where the wave light guide has a significantly greater distance from the neutral axis (AX1) to be assigned to the structure. 3. The neutral axis (A) of the structure (ST1)
The wave guide having a predetermined minimum distance from X1) has a smaller mechanical fragility (U111-U11).
Wave light guide according to claim 2, configured as U134). 4. In the case of a structure having connecting lines forming corners between the wave light guides located outside, the wave light guide (U) located in the corner area of this structure (ST1).
Optical cable according to any one of claims 1 to 3, wherein (111-U134) have a smaller mechanical fragility. 5. Smaller mechanical fragility (U11)
1 to U134) has a smaller MAC value than the other wave waveguides, and the MAC is MAC =
_Is given by MFD / λ _ceff , where MFD is the mode field diameter of the light guiding fiber,
The optical cable according to any one of claims 1 to 4, wherein _ceff is an effective limit wavelength. 6. For wave light guides (U111 to U134) having a smaller mechanical fragility, λ = 130.
The optical cable according to claim 5, wherein the MAC value is selected to be less than 7.4 at 0 nm. 7. A fragile wave light guide (E112 to E1)
33) Wave light guide that is not easily broken (U111 to U13
4) is at least 0.5 in their MAC value
Only, for example differing from each other by at least one.
Or the optical cable according to 6. 8. A wave light guide with a smaller mechanical fragility, wherein the wave light guide inside the structure (ST1) is capable of producing an increase in attenuation above the tolerance limit based on the arrangement of the structure in the finished cable. Optical cable according to any one of claims 1 to 7, which is replaced by a conductor (U111-U134). 9. A structure (ST1) is provided inside a U-shaped chamber element (CA1), which is more linear than other such elements.
The optical cable according to any one of claims 1 to 8. 10. The optical cable according to claim 1, wherein the structure (ST2) is housed inside a chamber element (CA21) having a substantially trapezoidal cross section. 11. The structure has a chamber-shaped recess (CA3).
Optical cable according to any one of claims 1 to 9, which is provided inside a profile body (CP3) provided with 1 to CA3n). 12. A structure (ST4) is housed inside a closed protective jacket (SH) and a plurality of strand elements of this kind are further linearized into one cable core. The optical cable according to any one of claims 1 to 9. 13. The entire wave light guide of the structure comprises:
13. An optical cable according to any one of claims 5 to 12 having a MAC value below 7.4, eg below 7.0. 14. The wave light guides (U111 to U134) in the region of higher mechanical loading are respectively wave guides (E112 to E13) in the region of lower mechanical load.
Optical cable according to any one of claims 1 to 13, having a greater layer thickness of their primary coating (PC) than 3). 15. A wave light guide (U111-U134) in the region of higher mechanical loading has a primary coating of 1.5-4 of the wave light guide (E111-E133) in the region of lower mechanical loading. Optical cable according to claim 14, having a layer thickness of .5 times, for example 2-3 times. 16. The primary coating of the wave light guides (U111-U134) in the region of higher mechanical loading comprises:
0.02-0.05mm For example 0.03-0.04mm
16. The optical cable of claim 15, having a layer thickness of. 17. Wave light guides (U111 to U134) in the region of higher mechanical loading respectively have wave light guides (E111 to E13) in the region of lower mechanical loading.
Optical cable according to any one of claims 1 to 16, having a material that is softer to its primary coating (PC) than 3). 18. The primary coating (PC) for wave light guides (U111-U134) in the region of higher mechanical loading than for wave light guides (E112-E133) in the region of low mechanical loading. Optical cable according to claim 17, characterized in that it is provided with a material which is 1 to 5 times softer, for example 1 to 2.5 times softer. 19. A primary coating (P) of a wave light guide (U111-U134) in the region of higher mechanical loading.
As material for C), elastic modulus 0.5-2.5MP
The optical cable according to claim 17 or 18, wherein the urethane acrylate having a is selected. 20. Wave light guides (eg U111, E11)
2, E113, U114) are provided in the wave light conductor-strip (for example, B11) forming the structure, and the wave light conductors (for example, U111, U114) located outside the strip structure are 2. A smaller mechanical fragility than the wave light guides (eg E112, E113) located inside this.
The optical cable according to any one of 1 to 19. 21. The optical cable according to claim 19, wherein a plurality of wave optical waveguide strips are assembled into a layered body forming a structure (ST1). 22. A wave light guide-band (for example, BL1) is constituted by a standard band (GB) having the following wave light guides (LW1 to LWn), that is, outside on the narrow side of the band. At the inside, the standard strip (GB)
By a standard strip having a wave light guide such that at least one wave light guide (eg LW1 *, LWn *) is additionally provided with a mechanical fragility smaller than that of the wave light guides (LW1 to LWn) of FIG. The optical cable according to claim 19 or 20, which is configured. 23. The wave light guides (LW1 *, LWn *) additionally provided on the side surface are respectively connected by a connecting means (VM).
22. The optical cable according to claim 21, wherein the optical cables are connected by. 24. The wave light guides (LW1 *, LW2 *) having a smaller mechanical fragility occupy the corner positions in the strip (BL2), respectively, and here the outer cover (AH2) is used. The optical cable according to claim 19 or 20, which is closed to. 25. A wave-shaped light guide (LW1 *, LW2 *) having a smaller mechanical fragility is a strip-shaped jacket (AH3).
The optical cable according to claim 19 or 20, wherein the optical cable is embedded inside a corner portion of the strip (BL3) inside. 26. Each wave light guide-strip (eg BL1, BL2 or BL3) is surrounded by an additional protective layer (BC).
The optical cable according to any one of 1 to 6 above. 27. The layered body forming the structure (ST1) is constituted by the same kind of wave light guide strips (BL1, BL2, BL3) according to claims 19 to 25. The optical cable according to item 1. 28. The laminated body forming the structure (ST1) is at the bottom and the top, and
25 Wave light guide strip (BL1, BL2, BL3)
The optical cable according to any one of claims 14 to 25, comprising: