KR102440833B1 - Ribbon-Tube Type Optical Cable - Google Patents

Abstract

The present invention relates to a ribbon tubular optical cable. Specifically, the present invention relates to a ribbon tube type optical cable capable of minimizing optical loss due to stress of an optical fiber ribbon accommodated in a loose tube while minimizing an outer diameter and weight.

Description

Ribbon-Tube Type Optical Cable

The present invention relates to a ribbon tubular optical cable. Specifically, the present invention relates to a ribbon tube type optical cable capable of minimizing optical loss due to stress of an optical fiber ribbon accommodated in a loose tube while minimizing an outer diameter and weight.

Optical cables deliver 15,000 to 16,000 times the amount of information compared to existing copper cables, so they are suitable for transmitting large-capacity multimedia information such as voice data and video, and have broadband that accommodates transmission rates of more than gigabit per second. Since the amount of light reduction is small, it can transmit over a much longer distance than copper wires without an amplifier in the middle, and has strong external noise, so it is widely used as a communication cable.

Such an optical cable is largely divided into a loose tube type, a ribbon tube type, a tight buffer type, and the like according to the structure of the optical unit constituting the optical cable.

1 shows a schematic cross-section of an optical unit 900 constituting a conventional ribbon tube type optical cable.

As shown in FIG. 1, the optical unit 900 constituting the ribbon tube-type optical cable is a fiber optic ribbon stack 910 in which a ribbon-formed optical fiber ribbon 911 consisting of a plurality of optical fibers is stacked in multiple layers is a tube 920. It has a structure that is accommodated loosely and can move freely to some extent.

Here, when the space in which the optical fiber ribbon laminate 910 can move in the tube 920 of the optical unit 900 is narrow, collision of the optical fiber ribbon laminate 910 and the inner wall of the tube 920, etc. By this, stress is applied to the optical fiber ribbon stack 910 and the optical fibers included therein, and as a result, there is a problem in that optical signal loss is induced.

On the other hand, in order to suppress optical signal loss due to collision between the optical fiber ribbon laminate 910 and the inner wall of the tube 920 , the space in which the optical fiber ribbon laminate 910 can move is widened in the tube 920 . When secured, jelly or the like is filled therein, and as a result, the outer diameter and weight of the optical unit 900 are increased.

Therefore, it is possible to minimize the optical signal loss while minimizing the increase in outer diameter and weight, and a ribbon tube type optical cable of a new structure having various capacities and configurations according to the user's needs is required. In particular, guidelines for optimized design according to the inner and outer diameter of the tube and the size of the ribbon stack are required.

An object of the present invention is to provide a ribbon tube-type optical cable capable of minimizing optical loss due to stress of an optical fiber ribbon accommodated in a loose tube while minimizing an outer diameter and weight.

In order to solve the above problems, the present invention provides a central tension line disposed in the center, an optical fiber ribbon laminate in which a plurality of layers of a ribbon-formed optical fiber ribbon composed of a plurality of optical fibers are stacked in a tube, which is disposed around the central tension line. A ratio (L) of a diagonal length (L) of the optical fiber ribbon stack to an inner diameter (Di) of the tube constituting the optical unit; /Di) can provide a ribbon tubular optical cable of 0.7 to 0.85.

In addition, the outer diameter of the optical cable may be 16 to 19 millimeters (mm).

Here, the weight per unit length of the optical cable may be 200 to 260 kg/km.

And, the outer diameter of the optical fiber may be 240 to 260 ㎛.

In this case, the number of optical fibers constituting the optical fiber ribbon may be eight.

In addition, the number of the optical unit may be six.

In addition, the difference between the inner diameter (Di) of the tube constituting the optical unit and the diagonal length (L) of the optical fiber ribbon laminate may be 0.5 to 1.0 millimeters (mm).

Here, the loss value of the 1550 nm wavelength optical signal loss test at room temperature may be 0.35 dB/km or less.

The ratio of the area of the optical fiber tube stack to the inner area of the tube may be 0.34 to 0.45.

In addition, the outside of the optical unit may be taped with a waterproof tape.

In this case, a waterproof yarn may be provided between a pair of adjacent optical units among the optical units or between the optical unit and the central tension line.

In addition, at least one rip cord may be provided inside the outer jacket.

Also, the central tension line may be taped with waterproof tape.

Here, the optical fiber ribbon is composed of eight 250 μm outer diameter optical fibers, the width of the optical fiber ribbon is 1.9 to 2.3 millimeters (mm), and the length (L) of the diagonal of the optical fiber ribbon stack is 2.7 to 2.8 millimeters ( mm), and the outer diameter of the optical cable may be 16 to 19 millimeters (mm).

In addition, the difference between the inner diameter (Di) of the tube and the diagonal length of the optical fiber ribbon laminate may be 0.5 to 1.0 millimeters (mm).

In addition, the tube of the light unit may be filled with a low-density jelly compound having a density of 0.2 to 0.5 g/cm 3 .

In this case, the low-density jelly compound may include a base oil, a gelling agent, and microspheres having a specific gravity of 0.023 to 0.028, and 0.1 to 1.6 parts by weight of a pour point depressant based on 100 parts by weight of the base oil.

In addition, the thickness of the tube of the light unit may be 0.53 to 0.62 millimeters (mm).

In addition, the thickness of the outer jacket may be 1.3 to 1.7 millimeters (mm).

Here, in order to solve the above problem, the present invention provides a central tension line disposed in the center, a ribbon-formed optical fiber ribbon arranged around the central tension line, and consisting of eight 250 μm outer diameter optical fibers, into six layers. The laminated optical fiber ribbon laminate includes six optical units accommodated in a tube and an outer jacket surrounding the exterior of the optical unit, and the diagonal length of the optical fiber ribbon laminate with respect to the inner diameter (Di) of the tube constituting the optical unit ( The ratio (L/Di) of L) is 0.7 to 0.85, the loss value of the optical signal loss test of 1550 nm wavelength at room temperature is 0.35 dB/km or less, and the outer diameter of the entire optical cable is 16 to 19 millimeters (mm) It can provide a ribbon tube type optical cable, characterized in that.

In this case, the width of the optical fiber ribbon may be 1.9 to 2.3 millimeters (mm), and the diagonal length L of the optical fiber ribbon stack may be 2.7 to 2.8 millimeters (mm).

In addition, the inner diameter of the tube of the light unit may be 3.1 to 3.9 millimeters (mm).

In addition, the thickness of the tube of the light unit may be 0.53 to 0.70 millimeters (mm).

Here, the ratio of the area of the optical fiber tube stack to the inner area of the tube may be 0.34 to 0.45.

In addition, the difference between the inner diameter (Di) of the tube and the diagonal length of the optical fiber ribbon laminate may be 0.5 to 1.0 millimeters (mm).

The ribbon tube type optical cable according to the present invention can minimize the optical signal loss and the outer diameter and weight of the cable by adjusting the ratio of the inner diameter of the tube constituting the optical unit and the size of the optical fiber ribbon stack accommodated in the tube.

In addition, according to the ribbon tube type optical cable according to the present invention, it provides an optimized ratio between the inner diameter of the tube constituting the optical unit and the size of the optical fiber ribbon stack accommodated in the tube, thereby satisfying the standard of room temperature loss required for the ribbon tube type optical cable. can do it

In addition, according to the ribbon tube type optical cable according to the present invention, an optimized ratio between the inner diameter of the tube constituting the optical unit and the size of the optical fiber ribbon laminate accommodated in the tube is provided, and the maximum loss according to the temperature change based on the loss value at room temperature Good results can be obtained in the temperature test, which determines whether or not the change value is measured.

1 shows a schematic cross-section of an optical unit constituting a conventional ribbon tube type optical cable.
Figure 2 shows a cross-sectional structure according to an embodiment of the ribbon tubular optical cable according to the present invention.
Figure 3 shows a cross-sectional structure according to another embodiment of the ribbon tube type optical cable according to the present invention.
Figure 4 shows a cross-sectional structure according to another embodiment of the ribbon tubular optical cable according to the present invention.
Figure 5 shows a cross-sectional structure according to another embodiment of the ribbon tube type optical cable according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout.

Figure 2 shows a cross-sectional structure according to an embodiment of the ribbon tubular optical cable according to the present invention. Specifically, Fig. 2 (a) shows a cross-sectional structure according to one embodiment of a ribbon tube type optical cable, and Fig. 2 (b) shows an enlarged view of the optical unit shown in area A of Fig. 2 (a). .

As shown in FIG. 2, the ribbon tube-type optical cable according to the present invention includes a plurality of central tension lines 100 and a plurality of ribbonized optical fiber ribbons 211 disposed around the central tension line 100 and composed of a plurality of optical fibers. The optical fiber ribbon stack 210 stacked in layers may include a plurality of optical units 200 accommodated in the tube 220 and an outer jacket 300 surrounding the outside of the optical unit. In particular, it may have a '1+6' structure in which six optical units 200 are arranged around one central tension line 100 .

The central tension line 100 performs a function of suppressing deformation of the entire optical cable and improving the tensile strength of the optical cable. The material of the central tension wire 100 is not particularly limited as long as it can perform the function of the central tension wire 100. For example, it may be made of high-strength fibers such as aramid fibers, synthetic resins with reinforcing fibers, etc. have.

In addition, moisture that has penetrated through the end of the stripped optical cable for connection with the junction box flows along the central tension line 100 made of aramid fibers, etc. In order to suppress penetration into the 200 , a waterproof layer 110 may be additionally included on the surface of the central tension line 100 . Here, the waterproof layer 110 may be formed by winding a waterproof tape having elasticity or coating a waterproof polymer.

The optical unit 200 is a ribbon-formed, that is, formed by coating a plurality of optical fibers arranged in a line with UV curable resin or the like, and an optical fiber ribbon laminate 210 in which a plurality of optical fiber ribbons 211 are laminated in a plurality of layers is a tube ( 220) may have a structure accommodated.

Here, the optical fiber constituting the optical fiber ribbon 211 has a double columnar structure in which a part called a cladding usually surrounds a part called a core in the center, where the core is Glass optical fiber made of silica material having a high refractive index is used, and the cladding is made of silica glass or synthetic resin having a relatively lower refractive index than the core, so that total reflection of light passing through the center occurs. It is implemented to play a role in transmitting a signal.

A single-mode optical fiber having a core diameter of several μm is referred to as a single-mode optical fiber, and a multi-mode optical fiber having a core diameter of several tens of μm is referred to as a step type or a hill type optical fiber according to the refractive index distribution of the core. The outer diameter of the optical fiber may be, for example, 200 μm or 250 μm.

The number of optical fibers included in one optical fiber ribbon 211 may vary depending on the data transmission efficiency that can be transmitted per unit time of the optical cable, the flexibility of the cable, etc., and may be, for example, 4 to 24, in the embodiment according to the present invention. It can be eight. The width and height of the optical fiber ribbon and the outer diameter of the optical fiber may be different according to the number of the optical fibers, for example, the width of the optical fiber ribbon may be 2.0 millimeters (mm) to 2.2 millimeters (mm).

In addition, from the viewpoint of increasing the density of the optical cable, it is advantageous as the height and width of the optical fiber ribbon 211 are smaller. However, when designing the optical fiber ribbon 211, the mechanical properties of the optical fiber and the handling problem during connection must also be considered, so that the appropriate size of the optical fiber ribbon 211 must be determined.

The optical fiber ribbon stack 210 may be formed by stacking the aforementioned optical fiber ribbon 211 in a plurality of layers. Here, the number of layers of the optical fiber ribbon forming the optical fiber ribbon stack 210 may vary depending on the data transmission efficiency that can be transmitted per unit time of the optical cable, the flexibility of the cable, etc., for example, in one optical fiber ribbon 211 . When the number of optical fibers included is 8, the number of layers of the optical fiber ribbon forming the optical fiber ribbon laminate 210 may be 4 to 8, preferably 6 pieces.

The tube 220 forming the optical unit 200 is usually made of a plastic resin such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), or polyamide (PA) such as nylon-12. It may be a plastic tube made of, preferably, a polypropylene (PP) tube in consideration of compatibility with a jelly compound to be described later as a waterproofing material that can be filled in the empty space in the tube 220 .

The tube 220 has a cylindrical shape as a whole, and has a structure having a through hole that is a space in which the optical fiber ribbon laminate 210 can be accommodated. Preferably, the tube 220 is formed with a color coating layer colored in different colors on the outside, so that it is easy to distinguish according to each function or action of the optical unit 200, It may be configured to be easily distinguished.

Here, the outer diameter / inner diameter and thickness of the tube 220 are determined according to the dimensions of the optical fiber ribbon stack 210 accommodated in the tube 220, mechanical strength and bending characteristics required in the optical cable, etc. For example, the thickness of the tube 220 may be preferably 0.53 to 0.62 millimeters (mm).

An empty space inside the tube 220 in which the optical fiber ribbon stack 210 is accommodated may be filled with a waterproofing material. The waterproofing material may include, for example, a jelly compound, a waterproofing powder, a waterproofing yarn, and the like.

The waterproofing material performs a function of preventing the moisture penetrating into the optical cable from penetrating into the optical fiber ribbon laminate 210 in the tube 220, and furthermore, the optical fiber ribbon laminate in the tube 220 ( 210) to ensure stable flow, thereby suppressing the stress applied to the optical fiber ribbon laminate 210 by friction between the inner wall of the tube 220 and the optical fiber ribbon laminate 210 and consequent optical signal loss perform the function

The jelly compound that can be used as the waterproofing material may be made of a polymer resin having excellent thermal stability, waterproofness, electrical insulation, etc., a mixture of a base oil and a gelling agent, etc. Since the viscosity is low and easy to remove, the workability for connection with the junction box is excellent, and in particular, since the density is about 0.2 to 0.5 g/cm 3 , preferably about 0.4 to 0.5 g/cm 3 , the conventional waterproofing material for tube filling Compared to that, the weight can be reduced by 10 to 15%, which is advantageous in reducing the weight of the optical cable.

The jelly compound consisting of a mixture of the base oil and the gelling agent may further include microspheres with a specific gravity of preferably 0.023 to 0.028 to achieve low viscosity and low density, and also based on 100 parts by weight of the base oil In addition, 0.1 to 1.6 parts by weight of a pour point depressant may be further included.

Stress is applied to the optical fiber ribbon stack 210 of the optical units 200 included in the optical cable due to various load conditions that may occur in the manufacturing process or installation environment of the optical cable, that is, elongation, bending, torsion, etc., thereby disconnection, deterioration of properties, etc. may be induced.

Therefore, in order to compensate for the strain of the optical cable due to the stress generated by the bending of the optical cable, etc., in order to give a margin to the length of the optical unit 200 and the optical fiber ribbon stack 210 included therein, the optical unit (200) may be aggregated around the central stretchability (100) with S-Z twist, helical twist, or the like.

In this case, the optical units 200 can maintain a twisted state at a certain pitch, and the pitch is a strain of the optical cable as the optical unit 200 twisted at this pitch is stretched by bending of the optical cable. ) may be appropriately selected in consideration of the outer diameter and bending radius of the optical cable to compensate.

Furthermore, the loose tube type optical cable mounted with a single optical fiber core is not affected by bending because individual optical fibers are independent, whereas the ribbon tube type optical cable is mounted with an optical fiber ribbon 211 in which several optical fibers are arranged in a row. When bending, each optical fiber has a different strain, which adversely affects optical loss.

That is, since the upper side of the optical fiber receives tension and the lower side receives compression with respect to the neutral axis inside the tube 220, it remains only when the tensioned portion and the compressed portion are evenly present within one pitch of the tube 220 where they are aggregated. In addition to reducing the strain rate, it is possible to prevent optical signal loss caused by the optical fiber ribbon stack 210 collide with the inner wall of the tube 220 .

Accordingly, not only the tube 220 constituting the optical unit 200, but also the optical fiber ribbon laminate 210 accommodated therein can maintain a twisted state at a constant pitch, and the optical fiber ribbon laminate 210 The twist pitch may be appropriately selected in consideration of the twist pitch of the tube 220 , the inner diameter of the tube 220 , the dimension of the optical fiber ribbon stack 210 , and the like.

In particular, in the ribbon tube type optical cable according to the present invention, the ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack 210 to the inner diameter (Di) of the tube 220 in the optical unit 200 ) to be within a certain range, thereby suppressing the stress applied to the optical fiber ribbon stack 210 and optical signal loss thereby achieving an effect of minimizing the increase in the outer diameter (Dc) and weight of the optical cable. can confirm that it is possible. A detailed description thereof will be described later with reference to Table 1.

The outer jacket 300 may be made of a polyethylene resin having excellent water resistance, electrical insulation, acid resistance, alkali resistance, thermal stability and excellent moldability, particularly medium density polyethylene (MDPE), or containing fluorine. polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), ethylenetetrafluoroethylene (ETFE), etc. or a combination thereof.

The thickness of the outer jacket 300 may be appropriately selected according to the purpose of the optical cable, specifically the overall outer diameter of the optical cable, required flexibility, bending characteristics, etc., and may be, for example, 1.3 to 1.7 millimeters (mm). An embodiment according to the present invention to be described later with reference to 1 is an example in which the thickness of the outer jacket 300 is 1.5 millimeters (mm).

In addition, the outer jacket 300 may include a stripe 700 of a specific color on its surface, and the stripe 700 may perform a function of identifying the manufacturer of the optical cable.

The ribbon tube type optical cable according to the present invention may further include a waterproof layer 400 inside the outer jacket 300 . Among the two waterproof layers 400, the waterproof layer 400 in contact with the optical unit 200 is formed by transversing a metal tape such as aluminum foil to the outside of the optical fiber unit 210, or is formed by a transparent film made of synthetic resin, a nonwoven fabric, etc. In addition to the function of suppressing the penetration of moisture penetrating through the damaged part of the outer jacket 300 into the optical cable, the optical unit 200 is wrapped around the outside to form a more circular shape. It functions to form the outer jacket 300 .

On the other hand, the waterproof layer 400 in contact with the outer jacket 300 among the two waterproof layers 400 is, for example, a water absorbing swellable tape made of a material such as a non-woven fabric to the optical unit 200 to the transverse winding. In addition to the function of suppressing the penetration of moisture penetrating through the damaged part of the outer jacket 300 into the optical cable, close adhesion with the polymer resin constituting the outer jacket 300 can be achieved. have.

In addition, in the ribbon tube type optical cable according to the present invention, the empty space between the outer jacket 300 and the optical unit 200 is filled with a bedding material made of a waterproof material such as jelly compound, waterproof powder, waterproof yarn 500. can

In particular, the waterproof yarn 500 is an empty space between the outer jacket 300 and the optical unit 200, in particular, between a pair of adjacent optical units 200 among the optical units 200 or the optical It may be interposed between the unit 200 and the central tension line 100, and a waterproof yarn having a waterproof powder attached to a continuous yarn or a waterproof yarn made by twisting or bonding a continuous yarn obtained by processing the waterproof powder into a thread form, etc. Available.

The waterproof yarn 500 may have, for example, a thickness of 300 to 3,000 denier, a swelling capacity of 20 g/g or more in distilled water, and a tensile strength of 3 to 150 N. When the thickness of the waterproof yarn is less than 300 denier, it is difficult to work because too many waterproof yarns 500 are needed to achieve the waterproof performance, and it causes an increase in the price of the optical cable. In addition, when the swelling capacity in distilled water of the waterproof yarn 500 is less than 20 g/g, it may be difficult to achieve the desired waterproof performance, and when the tensile strength is less than 3 N, in the process of entering into the empty space or optical cable Disconnection may occur due to the stress generated during bending of the

The ribbon tube type optical cable according to the present invention may further include at least one rip cord 600 under the outer jacket 300 . The rip cord 600 is used for the purpose of facilitating the peeling of the outer jacket 300 , and may also function as an additional tension line for improving the tensile strength of the optical cable.

The light unit shown in FIG. 2(b) is an embodiment in which the ribbon width (a) (mm) is about 2.1 millimeters (mm), and the ribbon stack height (h) (mm) is about 1.8 millimeters (mm). Therefore, the ribbon stack is arranged in a rectangular shape in which the difference in width and height is not large in the circular tube, and a certain amount of free space must exist in order to minimize the physical stress caused by the contact of the optical fiber in each corner area with the inner surface of the tube. can be guessed that This free space may be determined by the deviation of the diagonal length (L) of the ribbon tube stack 210 with respect to the inner diameter (Di) of the tube. However, if the car is made large, the diameter of the tube increases and the amount of jelly filled inside is increased, which may cause a problem in that the diameter and weight of the cable are increased together. Therefore, as will be described later, the relationship between the tube inner diameter (Di) and the diagonal length (L) of the ribbon tube stack 210 should be appropriately determined.

The weight per length of the ribbon tubular optical cable according to the present invention is preferably configured not to exceed 260 Kg/Km.

3 and 4 show a cross-sectional structure according to another embodiment of the ribbon tube type optical cable according to the present invention.

The ribbon tube type optical cable according to the present invention, as shown in FIG. 3, has a '1+6' structure in which five optical units 200 are arranged around one central tension line 100 and one intervening 800 is one. Also, as shown in FIG. 4 , it may have a '1+6' structure in which four optical units 200 and two intervening 800 are arranged around one central tension line 100 .

The interposition 800 shown in FIGS. 3 and 4 may be applied to replace the optical unit 200 according to an outer diameter determined during manufacture of the optical cable, and may have an outer diameter corresponding to the outer diameter of the optical unit 200, It may be made of a lightweight and inexpensive polymer resin, for example, polyethylene, polypropylene, or the like, in terms of weight reduction of the optical cable and reduction of manufacturing cost.

[Example]

1. Preparation example

A ribbon tube-type optical cable specimen according to each of Examples and Comparative Examples was prepared with the configuration shown in Table 1 below. Examples 1, 2, Comparative Example 1 and Comparative Example 2 have a '1+6' structure in which six optical units 200 are arranged around the central tension line 100, but as described above, It can be replaced for the purpose of reducing the weight of the optical cable and reducing the manufacturing cost according to the demand.

2. Physical property evaluation

1) Evaluation of optical signal loss

An optical signal loss test of 1550 nm wavelength was performed at room temperature (23° C.) on the ribbon tube-type optical cable specimen according to each of Examples and Comparative Examples, and the loss value was evaluated to be 0.35 dB/km or less to determine good or bad.

2) Temperature test

The ribbon tube-type optical cable specimen according to each of Examples and Comparative Examples was subjected to room temperature (23°C), -40°C for 24 hours, 70°C for 24 hours, -40°C again for 24 hours, again at 70°C for 24 hours, room temperature (23 ℃), an optical signal loss test of 1550nm wavelength was performed for each temperature change step, and the difference between the optical signal loss value at each temperature change step and the optical signal loss value at room temperature (23℃) If it is 0.1 dB/km or less, and the difference between the optical signal loss value and the optical signal loss value at room temperature (23°C) after being applied to the entire temperature change cycle is 0.2 dB/km or less, it is good, otherwise it is evaluated as bad.

The results of the physical property evaluation are shown in Table 1 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 rescue 1+6 1+6 1+6 1+6 number of optical units 6 6 6 6 Optical fiber outer diameter (㎛) 250㎛ 250㎛ 250㎛ 250㎛ Fibers per Ribbon 8 8 8 8 Number of fiber cores per ribbon stack 48 48 48 48 Total number of optical fibers 288 288 288 288 Ribbon Laminate
Diagonal length(L)(mm) 2.766 2.766 2.766 2.766 Ribbon stack height (h) (mm) 1.8 1.8 1.8 1.8 Ribbon width (a) (mm) 2.1 2.1 2.1 2.1 Ribbon height (mm) 0.3 0.3 0.3 0.3 Tube inner diameter (Di) (mm) 3.7 3.3 4.0 3 Tube Outer Diameter(Do)(mm) 4.9 4.4 5.3 4.0 Tube thickness (t) (mm) 0.6 0.55 0.65 0.5 Di-L(mm) 0.934 0.534 1.234 0.234 Ribbon Laminate
Diagonal length(L)(mm) /
Tube inner diameter (Di) (mm) 0.748 0.838 0.691 0.922 Ribbon laminate area (a*h)/tube inner area (S) 0.352 0.442 0.301 0.535 Outer jacket thickness (mm) 1.5 1.5 1.5 1.5 Cable outer diameter (mm) 18.6 16.8 19.8 15.8 Room temperature loss value (1550nm) (dB/km) 0.27 0.3 0.27 0.47 Weight per cable length (kg/km) 250 205 275 193 Temperature test (-40 to 70 degrees) Good Good Good error

In the ribbon tube type optical cable according to the present invention, when the optical fiber ribbon 211 is composed of eight optical fibers having an outer diameter of 250 μm, the width of the optical fiber ribbon 211 is 2.0 millimeters (mm) to 2.2 millimeters (mm), The length (L) of the diagonal of the optical fiber ribbon stack 210 may be 2.7 to 2.8 millimeters (mm), and the outer diameter of the optical cable may be 16 to 19 millimeters (mm).

According to the evaluation results of the embodiments described in Table 1, Examples 1 and 2 are examples in which all conditions such as signal loss value according to the required physical stress, temperature test, cable outer diameter, and weight per cable length are satisfied, Comparative Examples 1 and 2 are examples in which some of the above conditions are satisfied, but the other conditions are not satisfied, or the outer diameter or weight is excessively increased.

The main object of the present invention is to minimize the outer diameter and weight of the cable, and the object of the present invention is premised on satisfying the loss value condition and temperature test condition due to the physical stress of the optical fiber.

In particular, the condition related to the loss value is related to the physical stress that the ribbon stack is subjected to inside the tube, and it can be seen that it is related to the size of the spatial allowance inside the tube in which the ribbon stack is disposed.

Specifically, Comparative Example 1 satisfies the loss value in the 1 km (Km) test of the optical signal of 1550 nanometer (nm) wavelength as 0.27 (dB/km), which is 0.35 (dB/km) or less, Although the temperature test also obtained satisfactory results, it can be confirmed that the weight per 1Km length of the cable is close to 275 kilograms (Kg), so that it is not possible to achieve one of the objectives of the present invention, weight reduction. Through Examples 1 and 2, it can be confirmed that the weight per 1Km length of an appropriate cable satisfying the room temperature loss value condition and temperature test converges to about 200 kilograms (Kg) to 260 kilograms (Kg).

In Comparative Example 2, it can be seen that the weight reduction of the cable is achieved, but the loss value in the 1 km (Km) test of the optical signal of 1550 nanometer (nm) wavelength is 0.47 (dB) exceeding 0.35 (dB/km) /km), the loss value condition was judged to be bad, and the temperature test was also judged to be bad.

This is because the loss value and temperature test cannot be satisfied when the free space inside the tube becomes small, that is, when the diagonal length (L) (mm) / inner diameter (Di) (mm) of the ribbon stack approaches almost 1, so the official specification It can be understood to mean that the normal use required by the company is impossible.

Therefore, in order to achieve the object of the present invention, referring to Table 1, the ratio of the diagonal length (L) of the optical fiber ribbon stack 210 to the inner diameter (Di) of the tube 220 (L/Di) By controlling so as to be within a certain range, it is possible to achieve the effect of minimizing the increase in the outer diameter (Dc) and weight of the optical cable while suppressing the stress applied to the optical fiber ribbon stack 210 and optical signal loss caused thereby. It can be predicted that there is

Specifically, in the case of the optical unit 200, the inner diameter (Di) of the tube 220 and the diagonal length (L) of the optical fiber ribbon stack 210 in order to prevent optical signal loss from being present, there is a certain deviation and , since the number of optical fibers constituting the ribbon or the ribbon stack can be variously changed, the deviation also increases according to the size of the ribbon stack and the outer diameter of the tube in order not to cause optical signal loss due to each physical stress. should be

As shown in Table 1, when the width, height, and diagonal length of the ribbon stack are the same, the tube inner diameter value is 3.0 to 4.0 millimeters (mm) in Examples 1, 2, Comparative Examples 1 and 2 ) has

After all, in order to achieve the object of the present invention, the ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack 210 to the inner diameter (Di) of the tube 220 is about 0.7 to 0.85. In this case, it could be confirmed through various examples including Examples 1 and 2 that the objective can be achieved. This also confirms the fact that the inner diameter of the tube should be in the range of 3.1 to 3.9 millimeters (mm).

The ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon laminate 210 can be described as the ratio of the cross-sectional area of the optical fiber ribbon laminate 210 to the inner area S of the tube.

That is, it can be confirmed that the ribbon [laminated body area (a*h)/tube inner area (S)] in terms of area should satisfy the range of about 0.37. That is, the area occupied by the optical fiber tube stack among the tube inner area (S) should be about 34% to about 45%, and about 0.34 (34%) in consideration of the increase in the diameter and weight of the optical cable through the embodiments according to the present invention. ) to about 0.45 (45%).

In other words, when the [laminate area (a*h)/tube inner area (S)] is about 34% or less, it means that the free space inside the tube increases, which means that the loss value condition or temperature test condition cannot be satisfied. However, it means that the weight reduction of the cable cannot be achieved, and when it is about 45% or more, the free space inside the tube is small, so the loss value condition or temperature test is performed due to stress caused by friction with the inner tube surface and the edge of the ribbon stack. You can come to the conclusion that you are not satisfied.

Similarly, when 6 ribbons composed of 8 optical fibers shown in FIG. 2 are stacked to form an optical unit with a ribbon laminate, the inner diameter Di of the tube 220 and the optical fiber ribbon laminate 210 are When the difference (Di-L) of the diagonal length (L) is 0.5 to 1.0 millimeters (mm), it can be confirmed that the above loss value condition or temperature test is satisfied.

That is, in Comparative Example 1, the difference (Di-L) of the diagonal length (L) with respect to the inner tube diameter (Di) of the upper tube has a very large value of 1.234, and the ratio of the diagonal length (L) to the tube inner diameter (Di) ( L/Di) is lowered to 0.691, resulting in a space margin, but it can be seen that the weight per length of the cable is greatly increased, and Comparative Example 2 shows the difference (Di-) L) has a very small value of 0.234, and the ratio (L/Di) of the diagonal length (L) to the inner diameter (Di) of the tube is 0.922, which is almost 1, unlike Examples 1 and 2, in the tube This means that the space in which the tube stack is not movable is very narrow, and it can be confirmed that the optical signal may be lost by contacting or compressing the inner wall surface of the tube when the optical cable is bent or the like.

On the other hand, in the case of Examples 1 and 2 that satisfy the above conditions, the ribbon tube-type optical cable according to the present invention in which six ribbons composed of eight optical fibers having an outer diameter of 250 μm are stacked to constitute an optical unit as a ribbon stacked body at room temperature. It can be seen that the maximum loss value of the optical signal loss test of 1550 nm wavelength at 23℃ was measured to be 0.27 dB/km or 0.30 dB/km, which is 0.35 dB/km or less, which satisfies the room temperature loss value.

In this case, it can be confirmed that the outer diameter of the optical cable converges to about 16 to 19 millimeters (mm).

As shown in Table 1, the optical cable according to Comparative Example 2 can reduce the diameter of the cable, but it can be understood that the empty space inside the tube is too narrow to satisfy the normal temperature loss value of the optical cable due to physical stimulation. have.

In summary, in the optical cables of Examples 1 and 2 according to the present invention, the ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack to the inner diameter (Di) of the tube constituting the optical unit (L/Di) satisfies all the relationships of 0.7 to 0.85, and thus it can be understood that it is an optimized range that minimizes the outer diameter and weight of the optical cable despite achieving good room temperature optical signal loss and temperature test results.

The light unit shown in FIG. 2(b) is an embodiment in which the ribbon width (a) (mm) is about 2.1 millimeters (mm), and the ribbon stack height (h) (mm) is about 1.8 millimeters (mm). Therefore, the ribbon stack is arranged in a rectangular shape in which the difference in width and height is not large in the circular tube, and a certain amount of free space must exist in order to minimize the physical stress caused by the contact of the optical fiber in each corner area with the inner surface of the tube. can be guessed that

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all of them should be considered to be included in the technical scope of the present invention.

100: center tension line 200: optical unit
300: outer jacket 400: waterproof layer
500: waterproof yarn 600: lip code
700: stripe 800: intervening

Claims (25)

a central tension line placed centrally;
a plurality of optical units arranged around the central tension line and in which the optical fiber ribbon stack in which the ribbon-formed optical fiber ribbon composed of a plurality of optical fibers is stacked in a plurality of layers is accommodated in a tube; and,
Including; an outer jacket surrounding the outside of the light unit;
The ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack to the inner diameter (Di) of the tube constituting the optical unit is 0.7 to 0.85,
The ratio of the area of the optical fiber ribbon laminate to the inner area of the tube constituting the optical unit is 0.34 to 0.45,
The tube of the light unit is filled with a low-density jelly compound having a density of 0.2 to 0.5 g/cm 3 , and the low-density jelly compound includes a base oil, a gelling agent, and microspheres having a specific gravity of 0.023 to 0.028, Based on 100 parts by weight of the base oil, a ribbon tube type optical cable comprising 0.1 to 1.6 parts by weight of a pour point depressant. According to claim 1,
The ribbon tube type optical cable, characterized in that the outer diameter of the optical cable is 16 to 19 millimeters (mm). 3. The method of claim 2,
A ribbon tube type optical cable, characterized in that the weight per unit length of the optical cable is 200 to 260 kg/km. 4. The method according to any one of claims 1 to 3,
The outer diameter of the optical fiber is a ribbon tube type optical cable, characterized in that 240 to 260㎛. 4. The method according to any one of claims 1 to 3,
A ribbon tube type optical cable, characterized in that eight optical fibers constituting the optical fiber ribbon. 4. The method according to any one of claims 1 to 3,
Ribbon tube type optical cable, characterized in that the number of the optical unit is six. delete 4. The method according to any one of claims 1 to 3,
A ribbon tube type optical cable, characterized in that the loss value of the optical signal loss test of 1550 nm wavelength at room temperature is 0.35 dB/km or less. delete 4. The method according to any one of claims 1 to 3,
Ribbon tube type optical cable, characterized in that the outside of the optical unit is taped with a waterproof tape. 11. The method of claim 10,
A ribbon tube type optical cable, characterized in that a waterproof yarn is provided between a pair of adjacent optical units among the optical units or between the optical unit and the central tension line. 4. The method according to any one of claims 1 to 3,
Ribbon tube type optical cable, characterized in that at least one rip cord is provided inside the outer jacket. 4. The method according to any one of claims 1 to 3,
The central tension line is a ribbon tube type optical cable, characterized in that taped with a waterproof tape. a central tension line placed centrally;
a plurality of optical units arranged around the central tension line and in which the optical fiber ribbon stack in which the ribbon-formed optical fiber ribbon composed of a plurality of optical fibers is stacked in a plurality of layers is accommodated in a tube; and,
Including; an outer jacket surrounding the outside of the light unit;
The ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack to the inner diameter (Di) of the tube constituting the optical unit is 0.7 to 0.85,
The optical fiber ribbon is composed of eight optical fibers, the width of the optical fiber ribbon is 1.9 to 2.3 millimeters (mm), and the length (L) of the diagonal of the optical fiber ribbon stack is 2.7 to 2.8 millimeters (mm), and the optical cable is the outer diameter is 16 to 19 millimeters (mm),
The tube of the light unit is filled with a low-density jelly compound having a density of 0.2 to 0.5 g/cm 3 , and the low-density jelly compound includes a base oil, a gelling agent, and microspheres having a specific gravity of 0.023 to 0.028, Based on 100 parts by weight of the base oil, a ribbon tube type optical cable comprising 0.1 to 1.6 parts by weight of a pour point depressant. delete delete delete 4. The method according to any one of claims 1 to 3,
A ribbon tube type optical cable, characterized in that the thickness of the tube of the optical unit is 0.53 to 0.62 millimeters (mm). 4. The method according to any one of claims 1 to 3,
A ribbon tube type optical cable, characterized in that the thickness of the outer jacket is 1.3 to 1.7 millimeters (mm). a central tension line placed centrally;
6 optical units arranged around the central tension line, in which a fiber optic ribbon laminate in which a ribbon-formed optical fiber ribbon composed of 8 optical fibers is stacked in 6 layers is accommodated in a tube; and
It includes an outer jacket surrounding the outside of the optical unit,
The ratio (L/Di) of the diagonal length (L) of the optical fiber ribbon stack to the inner diameter (Di) of the tube constituting the optical unit is 0.7 to 0.85,
The ratio of the area of the optical fiber ribbon laminate to the inner area of the tube constituting the optical unit is 0.34 to 0.45,
The loss value of the optical signal loss test of 1550 nm wavelength at room temperature is 0.35 dB/km or less, and the outer diameter of the entire optical cable is 16 to 19 millimeters (mm),
The tube of the light unit is filled with a low-density jelly compound having a density of 0.2 to 0.5 g/cm 3 , and the low-density jelly compound includes a base oil, a gelling agent, and microspheres having a specific gravity of 0.023 to 0.028, Based on 100 parts by weight of the base oil, a ribbon tube type optical cable comprising 0.1 to 1.6 parts by weight of a pour point depressant. 21. The method of claim 20,
The width of the optical fiber ribbon is 1.9 to 2.3 millimeters (mm), and the length (L) of the diagonal of the optical fiber ribbon stack is 2.7 to 2.8 millimeters (mm). 22. The method of claim 20 or 21,
The inner diameter of the tube of the optical unit is a ribbon tube type optical cable, characterized in that 3.1 to 3.9 millimeters (mm). 22. The method of claim 20 or 21,
A ribbon tube type optical cable, characterized in that the thickness of the tube of the optical unit is 0.53 to 0.62 millimeters (mm). delete 22. The method of claim 20 or 21,
A ribbon tube type optical cable, characterized in that the difference between the inner diameter (Di) of the tube and the diagonal length of the optical fiber ribbon laminate is 0.5 to 1.0 millimeters (mm).

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