Multi-core optical cable

Abstract

The present invention relates to a multi-core optical cable, in which waterproof performance of each optical unit including a bundle member that accommodates a plurality of optical fibers and that has a variable shape may be secured, and which has a minimized outer diameter at the same time. The multi-core optical cable comprises: a plurality of optical units each including a bundle member including a plurality of optical fibers and a plurality of waterproof yarns assembled therein; and a cable jacket surrounding the plurality of optical units. The bundle members of the optical units may have a variable shape corresponding to the shape of a space in which same are disposed inside the cable jacket, and a moisture absorption rate per minute of the entire waterproof yarns accommodated in the optical units is 18 g / m or more.

Description

multicore optical cable

[0001] The present invention relates to a multi-core optical cable. More specifically, the present invention relates to a multi-core optical cable that comprises a bundle member that accommodates a plurality of optical fibers and has a variable shape, thereby ensuring waterproof performance for each optical unit while minimizing the outer diameter.

[0002] With the recent rise in demand for ultra-high-speed communications, demand for optical cable-based communications networks is also steadily increasing. Compared to conventional copper cables, optical cables offer greater bandwidth and are lighter and more compact, making them highly advantageous for building ultra-high-speed transmission networks.

[0003] In order to construct a large-capacity optical communication network, a multi-core optical cable includes a plurality of optical units inside a cable jacket, and each optical unit may be configured to include a tube containing a plurality of optical fibers or a bundle member such as a binder in which a plurality of optical fibers are collected.

[0004] Within each optical unit, a plurality of optical fibers can be accommodated within a bundle member in the form of individual optical fibers, but a structure in which a plurality of rollable optical fiber ribbons capable of widthwise rolling are accommodated within a single bundle member by bonding at least a portion of adjacent optical fibers among a plurality of optical fibers arranged in parallel in the longitudinal direction with a bonding material is also possible.

[0005] For multi-core optical cables equipped with multiple optical units, it is desirable to ensure waterproof performance while minimizing the outer diameter.

[0006] It is desirable for multicore optical cables to meet the waterproof performance standards ICEA S-87-640 and IEC 60794-1-22. These standards, which are waterproof performance standards for optical cables, assess whether leakage occurs in an optical cable specimen, 3 m or 40 m in length, when both ends are fixed at a depth of 1 m for 24 hours.

[0007] Since most water leakage phenomena can occur due to moisture penetrating into the empty space inside each optical unit constituting the optical cable, the waterproof performance of an optical cable including an optical unit capable of changing shape, such as the present invention, and having a high optical fiber density and very little empty space between optical units arranged adjacently inside the cable jacket can be considered to be mainly determined by the waterproof performance of each optical unit constituting the optical cable.

[0008] Therefore, when constructing a multi-core optical cable, a multi-core optical cable is required that can secure the waterproof performance of each optical unit and minimize the increase in the outer diameter of the optical cable.

[0009] The present invention aims to provide a multi-core optical cable having a minimized outer diameter while ensuring waterproof performance of each optical unit, which is configured to accommodate a plurality of optical fibers and includes a bundle member capable of changing shape.

[0010] In order to solve the above problem, a multi-core optical cable may be provided, comprising: a plurality of optical units comprising a plurality of optical fibers and a plurality of waterproof yarns; and a bundle member that collects at least the plurality of optical fibers and the plurality of waterproof yarns; and a cable jacket that wraps the plurality of optical units; wherein the bundle member of the optical unit is capable of changing its shape in response to the shape of a space arranged inside the cable jacket, and wherein the moisture absorption rate per minute of the entire waterproof yarn accommodated in each of the optical units is 18 g / m or more.

[0011] Here, the plurality of optical fibers can be accommodated inside the bundle member in the form of a plurality of rollable optical fiber ribbons.

[0012] In addition, the shortest distance between any one of the plurality of waterproof yarns accommodated inside the bundle member of the optical unit and the optical fiber located closest to the waterproof yarn may be no more than four times the diameter of the optical fiber.

[0013] And, among the plurality of waterproof yarns accommodated inside the bundle member of the optical unit, one waterproof yarn and two adjacent waterproof yarns may not simultaneously contact each other at the same point in the longitudinal direction of the optical cable.

[0014] Furthermore, the internal cable filling ratio according to the following [Formula 1] may be in the range of 55% to 85%.

[0015] [Formula 1]

[0016] Cable internal space factor (%) = (Total cross-sectional area of ​​optical fibers accommodated in the optical cable) / (Internal cross-sectional area of ​​cable jacket) * 100 (%)

[0017] Additionally, 10 to 19 waterproof yarns may be provided inside the bundle member of the optical unit.

[0018] Additionally, 20 to 30 waterproof yarns may be provided inside the bundle member of the optical unit.

[0019] In this case, the moisture absorption rate of each waterproof yarn accommodated inside the bundle member of the optical unit may be 1 g / m or more per minute.

[0020] And, the largest value among the internal dot ratios of the optical unit according to the following [Formula 2] may be 1.05 to 2 times the smallest value of the internal dot ratio of the optical unit.

[0021] [Formula 2]

[0022] Optical unit internal space factor (%) = (Total cross-sectional area of ​​optical fibers accommodated in bundle member) / (Internal cross-sectional area of ​​bundle member) * 100 (%)

[0023] Here, the largest value among the internal dot ratios of the optical unit according to the above [Formula 2] may be 1.05 to 1.6 times the smallest value of the internal dot ratio of the optical unit.

[0024] Additionally, the total thickness of the plurality of waterproof yarns accommodated inside the bundle member of the optical unit may be in the range of 11,000 denier to 26,000 denier.

[0025] In this case, the thickness of each waterproof yarn inside the bundle member of the optical unit may be in the range of 500 denier to 2500 denier.

[0026] In addition, the above waterproof yarn can be coated with a super absorbent polymer (SAP) in powder form.

[0027] Here, the highly absorbent waterproof material can provide a waterproof function by changing into a jelly or gel form when in contact with moisture.

[0028] Additionally, 70 to 199 optical fibers may be provided inside the bundle member of the optical unit.

[0029] Furthermore, 200 to 300 optical fibers may be provided inside the bundle member of the optical unit.

[0030] Additionally, 10 to 19 optical units may be provided inside the cable jacket.

[0031] Additionally, 20 to 30 optical units may be provided inside the cable jacket.

[0032] In addition, the cable jacket may include a binding member that wraps the outer side of the plurality of optical units.

[0033] Additionally, the cable jacket may further include a plurality of tension members embedded in the length direction of the cable.

[0034] In this case, the plurality of tension members may include a pair of tension members each arranged adjacent to each other at positions symmetrical to each other with respect to the center of the optical cable.

[0035] Additionally, at least one notch portion may be formed on the inside of the cable jacket, and a rip cord may be provided in the space inside the notch portion.

[0036] Here, a protrusion may be formed in an area corresponding to the position where the notch is formed among the outer peripheral area of ​​the cable jacket.

[0037] Furthermore, the overall outer diameter of the multi-core optical cable may be in the range of 25 millimeters to 40 millimeters (mm).

[0038] According to the multi-core optical cable according to the present invention, the waterproof performance of each optical unit is excellently secured by including a bundle member that accommodates a plurality of optical fibers and is capable of changing its shape in accordance with the shape of the inner surface of the cable jacket, thereby enabling the multi-core optical cable comprising a plurality of optical units to implement waterproof performance in accordance with the standards ICEA S-87-640 and IEC 60794-1-22.

[0039] In addition, according to the multi-core optical cable according to the present invention, the waterproof performance of each optical unit can be improved by dispersing a plurality of waterproof yarns included within each optical unit and adjusting the internal dot ratio of the optical unit, the thickness of the waterproof yarns included within the optical unit, and the number of waterproof yarns within an appropriate range.

[0040] In addition, according to the multi-core optical cable according to the present invention, by applying a bundle member such as a tube or binder whose shape can be changed as a component of an optical unit and limiting the internal filling ratio of each optical unit to an appropriate range, the waterproof performance of each optical unit can be secured while minimizing the overall outer diameter of the optical cable.

[0041] FIG. 1 illustrates a cross-sectional view of one embodiment of a multi-core optical cable according to the present invention.

[0042] Figure 2 illustrates a cross-sectional view of another embodiment of a multi-core optical cable according to the present invention.

[0043] FIG. 3 illustrates a cross-sectional view of one optical unit constituting a multi-core optical cable according to the present invention.

[0044] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached 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 to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0045] FIG. 1 illustrates a cross-sectional view of one embodiment of a multicore optical cable according to the present invention, FIG. 2 illustrates a cross-sectional view of another embodiment of a multicore optical cable according to the present invention, and FIG. 3 illustrates a cross-sectional view of one optical unit constituting a multicore optical cable according to the present invention.

[0046] A multi-core optical cable (100) according to the present invention relates to a multi-core optical cable having, for example, 1728, 3456 or 6912 optical fibers (11), and is characterized by having a structure that enables minimization of the outer diameter while ensuring waterproof performance of each optical unit (10).

[0047] In order to ensure convenience and identification during connection work, the multi-core optical cable (100) may be configured by configuring a plurality of optical units (10) each containing a plurality of optical fibers (11), and then assembling the plurality of optical units (10) again and covering them with a cable jacket (30).

[0048] Specifically, a multi-core optical cable (100) according to the present invention may be configured to include a plurality of optical units (10) including a plurality of optical fibers (11) and a plurality of waterproof yarns (13); and a bundle member (12) that collects at least the plurality of optical fibers (11) and the plurality of waterproof yarns (13); and a cable jacket (30) that wraps the plurality of optical units (10).

[0049] Here, the bundle member (12) of the optical unit (10) may have a feature in which the shape of the cross-section changes in the longitudinal direction when placed inside the cable jacket (30) with multiple optical fibers (11) accommodated therein.

[0050] The multi-core optical cable (100) illustrated in FIG. 1 is an embodiment having a structure in which 22 optical units (10) are provided inside a cable jacket (30), 288 optical fibers (11) are accommodated inside each optical unit (10), and the 288 optical fibers (11) are formed by 24 rollable optical fiber ribbons (11R) capable of being rolled in the width direction, each of which is composed of 12 optical fibers (11). In this case, the outer diameter (D1) of the cable jacket (30) constituting the multi-core optical cable (100) can be formed in a range of 25 millimeters to 33 millimeters (mm).

[0051] The multi-core optical cable (100) illustrated in FIG. 2 is another embodiment having a structure in which 12 optical units (10) are provided inside a cable jacket (30), 288 optical fibers (11) are accommodated inside each optical unit (10), and the 288 optical fibers (11) are formed by 24 rollable optical fiber ribbons (11R) capable of being rolled in the width direction, each of which is composed of 12 optical fibers (11). In this case, the outer diameter (D2) of the cable jacket (30) constituting the multi-core optical cable (100) can be formed in a range of 30 millimeters to 40 millimeters (mm).

[0052] Some of the plurality of optical units (10) constituting the multi-core optical cable (100) according to the present invention may be arranged on the inside of the cable jacket (30) with a central portion of the cross-section perpendicular to the longitudinal direction of the multi-core optical cable (100) to form an inner layer, and the rest may be arranged on the outer periphery of the plurality of optical units (10) forming the inner layer to form an outer layer.

[0053] That is, the plurality of optical units (10) constituting the above multi-core optical cable (100) may be formed into a multi-layer structure including an inner layer and an outer layer inside the cable jacket (30).

[0054] Here, the multi-core optical cable (100) may have a structure in which a plurality of optical units (10) forming an inner layer and a plurality of optical units (10) forming an outer layer inside the cable jacket (30) are assembled at once and are wound transversely in the same direction.

[0055] In addition to this, the multi-core optical cable (100) may have a structure in which a plurality of optical units (10) forming an inner layer inside a cable jacket (30) are assembled and transversely wound in one direction, while a plurality of optical units (10) forming an outer layer are assembled and transversely wound in the other direction opposite to the transverse winding direction of the inner layer.

[0056] The number of optical units (10) accommodated within the cable jacket (30) may be increased or decreased. In one embodiment, the number of optical units (10) accommodated within the cable jacket (30) may be in the range of 10 to 19. In another embodiment, the number of optical units (10) accommodated within the cable jacket (30) may be in the range of 20 to 30.

[0057] The number of optical fibers (11) accommodated within the bundle member (12) constituting the optical unit (10) may increase or decrease. In one embodiment, the number of optical fibers (11) accommodated within the bundle member (12) constituting the optical unit (10) may be in the range of 70 to 199. In another embodiment, the number of optical fibers (11) accommodated within the bundle member (12) constituting the optical unit (10) may be in the range of 200 to 300.

[0058] The number of optical fibers constituting one rollable optical fiber ribbon (11R) accommodated within the bundle member (12) constituting the above optical unit (10) can be increased or decreased. Preferably, the number of optical fibers (11) constituting one rollable optical fiber ribbon (11R) is 6 or more.

[0059] The above-mentioned rollable optical fiber ribbon (11R) may have a structure in which a plurality of optical fibers (11) are arranged in parallel in the longitudinal direction of the optical fiber ribbon, and a pair of adjacent optical fibers (11) among the plurality of optical fibers (11) are bonded with a bonding material.

[0060] The bonding material used in the above-mentioned rollable optical fiber ribbon (11R) may include a UV-curable resin or the like, and the bonding material may be intermittently applied along the longitudinal direction of the optical fiber (11) to the area between a pair of optical fibers (11) to enable width-wise rolling of the optical fiber ribbon.

[0061] Since the above-mentioned rollable optical fiber ribbon (11R) is configured to be able to roll in the width direction, it can be accommodated inside the bundle member (12) in a curved shape based on the cable cross-section.

[0062] As shown in FIGS. 1 and 2, when each adjacent optical fiber (11) included in a rollable optical fiber ribbon (11R) is connected based on the cable cross-section, a curved shape is formed, thereby allowing a plurality of rollable optical fiber ribbons (11R) to be accommodated inside the bundle member (12).

[0063] The bundle member (12) constituting the optical unit (10) may be maintained in a circular, oval or polygonal shape while a rollable optical fiber ribbon (11R) is accommodated therein, and when the bundle member (12) is a tube (121), it may be made of a material having a thin thickness, relatively low hardness, low elastic modulus or flexibility, and its shape may be changed to correspond to the shape of the space arranged within the cable jacket (30).

[0064] Here, the thickness of the tube (121) may be formed in a range of 0.1 millimeter to 0.5 millimeter (mm), and the circumference of the tube (121) may be formed in a range of 15 millimeter to 25 millimeter (mm).

[0065] In addition, the tube (12) may be made of a polyolefin resin material having a Shore D hardness of about 20 to 40, and the polyolefin resin may have its flame retardancy enhanced by adding a halogen-free flame retardant.

[0066] The optical unit (10) composed of such a bundle member (12) can minimize the overall outer diameter of the optical cable by changing its shape according to the shape of the space when the internal space of the cable jacket (30) is narrow, as shown in FIG. 1, thereby minimizing waste of the internal space of the optical cable.

[0067] However, if there is ample space inside the cable jacket (30), as shown in FIG. 2, the shape of the optical unit (10) in which the bundle member (12) is a tube (121) can be restored to a circular shape. That is, if the optical unit is adjacent, the shape can be flexibly changed to respond to the environment in which the optical unit is accommodated by the relatively low hardness, low elastic modulus, or flexible material of the polyolefin resin material applied to the tube (121) of about 0.1 millimeter to 0.5 millimeter (mm), thereby contributing to the reduction of the overall outer diameter of the optical cable.

[0068] The multi-core optical cable (100) according to the present invention can be configured to satisfy waterproof performance according to the international standard IEC 60794-1-22 or the outdoor cable standard ICEA S-87-640 specified in North America.

[0069] As mentioned above, the waterproof performance test in IEC 60794-1-22 and ICEA S-87-640, which are standards for the waterproof performance of optical cables, evaluates whether leakage occurs in an optical cable specimen with a length of 3 m or 40 m when both ends are fixed at a water depth of 1 m for 24 hours.

[0070] Meanwhile, when evaluating the waterproof performance of an optical cable, a water leak occurs when moisture penetrates into the empty space inside each optical unit constituting the optical cable. Therefore, in order to secure excellent waterproof performance of the optical cable, the waterproof performance of each optical unit constituting the optical cable must be guaranteed.

[0071] In addition, when evaluating the waterproof performance of an optical cable in a waterproof performance test according to standards IEC 60794-1-22 and ICEA S-87-640, if no leakage occurs when the optical cable specimen length is short, the waterproof performance can be considered excellent.

[0072] Accordingly, in order to implement excellent waterproof performance of the multi-core optical cable (100) according to the present invention, which prevents leakage of water in the optical cable specimen even when a waterproof test is performed using a relatively short optical cable specimen of 3 m in length among the test conditions of the standards IEC 60794-1-22 and ICEA S-87-640, the waterproof performance of each optical unit (10) constituting the multi-core optical cable (100) was reinforced.

[0073] Specifically, each optical unit (10) constituting the multi-core optical cable (100) according to the present invention may be provided with a plurality of waterproof yarns (13) having waterproof performance inside the bundle member (12), and the moisture absorption rate per minute of the entire waterproof yarn (13) accommodated inside each optical unit (10) may be 18 g / m or more.

[0074] That is, for each optical unit (10), if the moisture absorption rate of the entire waterproof yarn (13) contained in the bundle member (12) of the optical unit (10) per unit length (m) of the bundle member (12) is configured to be 18 g / m or more per minute, a multi-core optical cable (100) configured by assembling a plurality of such optical units (10) can sufficiently satisfy the waterproof performance test standards according to the standards IEC 60794-1-22 and ICEA S-87-640.

[0075] Hereinafter, with reference to FIG. 3, the optical unit (10) constituting the multi-core optical cable (100) according to the present invention will be examined in more detail.

[0076] As shown in Fig. 3, a plurality of waterproof yarns (13) can be provided in the empty space inside the bundle member (12) along the length of the cable inside each optical unit (10).

[0077] The above waterproof yarn (13) can be manufactured by coating or containing a waterproof material on a synthetic fiber made of a polymer material such as polyester, and winding a plurality of fibers containing the waterproof material horizontally. The waterproof material may be a waterproof powder or a waterproof jelly.

[0078] Preferably, the waterproof yarn (13) may include a super absorbent polymer (SAP). The super absorbent polymer (SAP) is a functional resin that has the ability to absorb and retain moisture, such as water, in an amount tens to thousands of times its own weight.

[0079] The above-mentioned highly absorbent waterproofing material (SAP) is normally in powder form, but when it comes into contact with moisture, it changes into a form of waterproof jelly or gel, and expands in volume to fill the empty space inside the optical unit (10), thereby providing a waterproofing function.

[0080] The waterproofing properties of a cable are determined by the size and shape of the space within the cable through which water can flow, and are realized by placing the required amount of waterproof yarn (13) in an appropriate location within this space. When water penetrates, the waterproof yarn (13) absorbs the penetrated water and expands, and the gelled SAP contained in the waterproof yarn (13) blocks the void through which water can flow, thereby providing a waterproofing function. In particular, the rapid absorption of the penetrated water by the waterproof yarn (13) is an important factor in achieving excellent waterproofing properties.

[0081] The moisture absorption rate of each of the above waterproof yarns (13) can be evaluated in the following manner. First, prepare three samples with a length of 1 m ± 1 mm. Each sample is wound to a diameter of about 5 to 6 cm and firmly fixed so that it does not unravel. Then, the dry weight (W) of each sample is dry ) is measured with an accuracy of 1 mg. Next, immerse each sample in a beaker containing more than 200 ml of distilled water so that it is completely submerged. If the sample floats due to air bubbles, remove the bubbles to ensure that the sample is completely submerged. After 1 minute of placing the sample in water, take it out and hang it for 2 minutes to naturally dry, and then measure the wet weight (W wet ) is measured.

[0082] Moisture absorption rate is W wet In W dry It is calculated as the value minus the absorption rate, and the unit is g / m / 1min. The final absorption rate value is calculated by taking the average value of the absorption rates measured in three samples.

[0083] Meanwhile, the moisture absorption rate per minute of the entire waterproof yarn (13) accommodated in each of the above-described light units (10) can be calculated by multiplying the moisture absorption rate of each waterproof yarn (13) by the number of waterproof yarns (13) accommodated in each light unit (10). In other words, the moisture absorption rate of the entire waterproof yarn accommodated in the light unit (10) is calculated by reflecting the total number of waterproof yarns in the amount of moisture absorbed per minute by each waterproof yarn.

[0084] The above-described highly absorbent waterproofing material (SAP) may include at least one selected from the group consisting of a cross-linked acrylic acid polymer, a cross-linked vinyl alcohol-acrylate copolymer, a cross-linked maleic anhydride grafted polyvinyl alcohol, a cross-linked acrylate-methacrylate copolymer, a cross-linked methyl acrylate-vinyl acetate copolymer, a cross-linked starch-acrylate graft copolymer, a cross-linked starch-acrylonitrile graft copolymer, a cross-linked carboxymethyl cellulose, a cross-linked isobutylene-maleic anhydride copolymer, and the like.

[0085] In addition, the plurality of waterproof yarns (13) accommodated inside the bundle member (12) of the optical unit (10) change in shape and volume when in contact with moisture, and in order to effectively fill the empty space inside the optical unit (10), it is preferable that the plurality of waterproof yarns (13) are dispersed and arranged in the empty space inside the optical unit (10).

[0086] Here, the distributed arrangement of a plurality of waterproof yarns (13) means that a plurality of rollable optical fiber ribbons (11R) made of a plurality of optical fibers (11) are accommodated inside the optical unit (10) and a plurality of waterproof yarns (13) are evenly distributed in the space around each optical fiber (11) or in the empty space between the optical fiber (11) and the inner surface of the bundle member (12).

[0087] The multi-core optical cable (100) according to the present invention is characterized in that, in order to control the dispersion characteristics of a plurality of waterproof yarns (13) in the empty space inside the optical unit (10), the shortest distance (d) between any one waterproof yarn (13) among a plurality of waterproof yarns (13) and the optical fiber (11) located closest to the waterproof yarn (13) inside the bundle member (12) of the optical unit (10) is configured to be 4 times or less the diameter of the optical fiber (11).

[0088] If the shortest distance (d) between one of the plurality of waterproof yarns (13) and the optical fiber (11) closest to the waterproof yarn (13) is more than four times the diameter of the optical fiber (11), the plurality of waterproof yarns (13) are not evenly distributed around the optical fiber (11) in the empty space inside the optical unit (10), and thus the arrangement structure of the waterproof yarns (13) cannot sufficiently protect each optical fiber (11) from moisture.

[0089] In addition, it is characterized in that among the plurality of waterproof yarns (13) inside the bundle member (12) of the optical unit (10), one waterproof yarn (13) does not come into contact with two adjacent other waterproof yarns (13) at the same point in the longitudinal direction of the multi-core optical cable (100).

[0090] The waterproof performance of each optical unit (10) constituting the multi-core optical cable (100) according to the present invention is closely related to the density of the waterproof yarn (13) accommodated inside the bundle member (12) of the optical unit (10). Therefore, the multi-core optical cable (100) according to the present invention can improve the waterproof performance of each optical unit (10) by adjusting the internal optical unit filling ratio of each optical unit (10), the thickness of the waterproof yarn (13) included inside one optical unit (10), and the number of waterproof yarns (13) to appropriate ranges.

[0091] In a state where multiple optical fibers (11) are accommodated inside each optical unit (10), the cable internal occupancy rate calculated by the following [Formula 1] can be configured in the range of 55% to 85%.

[0092] [Formula 1]

[0093] Cable internal space factor (%) = (Total cross-sectional area of ​​optical fiber (11) accommodated in optical cable (100)) / (Internal cross-sectional area of ​​cable jacket (30)) * 100 (%)

[0094] As described above, since the bundle member (12) of the optical unit (10) is made of a material whose cross-sectional shape can be changed when placed inside the cable jacket (30), the internal cross-sectional area of ​​the bundle member (12) of the optical unit (10) can be changed, and the internal dot ratio of each optical unit calculated by the following [Formula 2] can have the characteristic of being changed.

[0095] [Formula 2]

[0096] Optical unit internal space factor (%) = (Total cross-sectional area of ​​optical fibers accommodated in bundle member) / (Internal cross-sectional area of ​​bundle member) * 100 (%)

[0097] For example, when the optical unit (10) is accommodated inside a cable jacket (30), it can be deformed into an irregular shape corresponding to the shape of the space in contact with the inner surface of the cable jacket (30) and the surrounding optical unit (10), and at that time, the optical unit internal dot ratio of the optical unit (10) can be changed.

[0098] Here, when the internal cable space ratio is 55% to 85%, the cross-sectional area occupied by each optical unit (10) is sufficiently evenly distributed so that a specific optical unit (10) is not excessively pressurized or contains excessive empty space. Preferably, the largest value among the internal cable space ratios of the optical units may be 1.05 to 2 times the smallest value, and more preferably, it may be 1.05 to 1.6 times or less.

[0099] In the case where the internal space factor of the above-mentioned cable is less than 55%, the cross-sectional area occupied by each optical unit (10) is not evenly distributed, and the empty space area inside some optical units (10) increases excessively, so that the space that cannot be covered by multiple waterproof yarns (13) becomes larger, which may result in a decrease in waterproof performance, and the outer diameter of the optical unit (10) may increase unnecessarily, which may increase the overall outer diameter of the multi-core optical cable (100) composed of the same.

[0100] On the other hand, when the internal filling ratio of the cable exceeds 85%, it may contribute to reducing the overall outer diameter of the multi-core optical cable (100), but if a specific optical unit (10) is excessively pressurized, the empty space inside the bundle member (12) is insufficient, so that the plurality of waterproof yarns (13) arranged inside the bundle member (12) are not densely packed in a specific area and are not evenly distributed, which may deteriorate the waterproof performance. In addition, if the waterproof yarn (13) absorbs moisture and swells in the insufficient empty space inside the bundle member (12), it may pressurize the adjacently arranged optical fiber (11), which may cause excessive micro-bending loss or damage to the optical fiber.

[0101] In this way, the multi-core optical cable (100) according to the present invention can secure the waterproof performance of the multi-core optical cable (100) and minimize the overall outer diameter of the multi-core optical cable (100) by applying a bundle member (12) whose shape can be changed as a component of the optical unit (10) and limiting the internal filling ratio of the cable to an appropriate range.

[0102] In this way, when the internal cable filling ratio is adjusted to a range of 55% to 85%, the waterproof yarn (13) can be provided in a range of 10 to 19 in the empty space inside the bundle member (12) of the optical unit (10).

[0103] In addition, the waterproof yarn (13) may be provided in the range of 20 to 30 in the empty space inside the bundle member (12) of the optical unit (10) while the internal cable filling ratio is adjusted to a range of 55% to 85%.

[0104] In addition, the moisture absorption rate of the individual waterproof yarns (13) of the waterproof yarns (13) accommodated in the empty space inside the bundle member (12) of the light unit (10) may be configured to be 1 g / m or more per minute.

[0105] Inside the bundle member (12) of each optical unit (10), a plurality of waterproof yarns (13) may be provided in at least one area among the space between the inner surface of the bundle member (12) and the optical fiber (11), the space between the plurality of rollable optical fiber ribbons (11R), and the space between the plurality of optical fibers (11) constituting one rollable optical fiber ribbon (11R).

[0106] If the number of waterproof yarns (13) accommodated within one optical unit (10) is less than 10, the waterproof yarns (13) cannot be effectively distributed in the empty space within the bundle member (12), so the space between the optical fiber (11) and the waterproof yarns (13) increases significantly, which may result in a deterioration in waterproof performance.

[0107] On the other hand, if the number of waterproof yarns (13) accommodated inside one optical unit (10) exceeds 30, the density of waterproof yarns (13) inside the bundle member (12) excessively increases, so that the fluidity of waterproof materials such as waterproof jelly in the empty space inside the bundle member (12) is reduced, which may result in a problem in that the waterproof performance may actually be reduced.

[0108] And, a plurality of waterproof yarns (13) are provided in the empty space inside the bundle member (12) of the optical unit (10), and as described above, among the plurality of waterproof yarns (13), the plurality of waterproof yarns (13) can be distributed in the empty space inside the bundle member (12) such that the shortest distance (d) between the waterproof yarn (13) and the optical fiber (11) located closest to the waterproof yarn (13) is less than four times the diameter of the optical fiber (11).

[0109] In addition, the total thickness of the plurality of waterproof yarns (13) inside the bundle member (12) of each optical unit (10) may be in the range of 11,000 denier to 26,000 denier, and the thickness of each waterproof yarn (13) provided inside the bundle member (12) may be in the range of 500 denier to 2,500 denier.

[0110] Here, when the total thickness of the plurality of waterproof yarns (13) provided inside the optical unit (10) exceeds 26,000 denier or the thickness of one waterproof yarn (13) provided inside the optical unit (10) exceeds 2,500 denier, the fluidity of the waterproof material flowing out from the waterproof yarn (13) when it comes into contact with moisture inside the bundle member (12) of the optical unit (10) is reduced, and the internal gap of the bundle member (12) cannot be effectively blocked.

[0111] On the other hand, if the total thickness of the plurality of waterproof yarns (13) provided inside the optical unit (10) is less than 11,000 denier or the thickness of one waterproof yarn (13) provided inside the optical unit (10) is less than 500 denier, the density of the waterproof yarns based on the same number of waterproof yarns (13) is reduced, so that empty space increases inside the bundle member (12) of the optical unit (10), and thus the waterproof performance may be reduced.

[0112] The multi-core optical cable (100) according to the present invention may further include a binding member (20) that wraps the outer side of the plurality of optical units (10) on the inner surface of the cable jacket (30).

[0113] A plurality of optical units (10) can be twisted or bound at a predetermined pitch or assembled using a binding member (20) to reinforce the waterproof function of the optical cable (100) to form a cable core. The binding member (20) may be in the form of a tape or a binding yarn, etc.

[0114] In addition, the multi-core optical cable (100) according to the present invention may further include a plurality of tensile members (40) embedded in the cable jacket (30) in the longitudinal direction of the cable. The plurality of tensile members (40) serve to reinforce the tensile strength or tensile strength of the cable.

[0115] The above tensile member (40) may be configured in the form of a wire and may be provided along the length of the cable so as to be embedded inside the cable jacket (80) when the cable jacket (80) is extruded.

[0116] A plurality of tension members (40) may be configured to include a pair of tension members (40) each positioned adjacent to each other at symmetrical positions with respect to the center of the optical cable (100).

[0117] In the embodiment illustrated in FIGS. 1 and 2, the multi-core optical cable (100) according to the present invention is configured to include four tension members (40) inside the cable jacket (30), and two tension members (40) are provided symmetrically inside the cable jacket (30) while two tension members (40) are adjacent to each other. However, the number of tension members (40) can be increased or decreased.

[0118] Each of the above tensile members (40) may be configured in the form of a wire, and the above tensile members (40) may be made of a non-metallic material such as fiber-reinforced plastic (FRP), aramid-reinforced plastic (ARP), aramid yarn, glass yarn, polyester yarn, nylon yarn, or a metallic material such as galvanized steel wire.

[0119] Preferably, the tensile member (40) may be made of a metal material such as galvanized steel wire. In this case, since the tensile member (40) made of a metal material can provide greater tensile strength with a smaller outer diameter than the tensile member (40) made of a non-metallic material, the outer diameter of the tensile member (40) can be reduced, and thus the overall outer diameter of the multi-core optical cable (100) can be minimized.

[0120] In addition, the multi-core optical cable (100) according to the present invention may have at least one notch portion (n) formed on the inside of the cable jacket (30), and a rip cord (50) may be provided in the internal space of the notch portion (n).

[0121] In this way, the multi-core optical cable (100) according to the present invention forms at least one notch portion (n) on the inner surface of the cable jacket (30) and has a rip cord (50) inside the notch portion (n), so that the cable jacket (30) can be easily stripped to expose the core (C) of the optical cable during the process of connecting the multi-core optical cable (100) to another optical fiber, such as an intermediate branch, thereby improving stripping workability.

[0122] In the embodiment illustrated in FIGS. 1 and 2, the notch portions (n) are provided in a total of two, and are illustrated as being formed one at each of the two notch portions (n) facing each other, but the number may be increased or decreased.

[0123] The above notch portion (n) may be formed in a groove shape with rounded corners on the inner surface of the cable jacket (30) so that the internal optical unit (10) is not damaged when the cable jacket (30) is removed, and the above notch portion (n) may be formed in a shape in which the thickness decreases in the radial direction on the inner surface of the cable jacket (30).

[0124] In this way, since the notch portion (n) is formed on the inner surface of the cable jacket (30) and a void space is formed between the cable jacket (30) and the binding member (20), the cable jacket (30) in the area where the notch portion (n) is located can be removed lengthwise or the rip cord (50) in the notch portion (n) can be partially exposed without damaging it, and then the cable jacket (30) can be torn and removed by pulling the rip cord (50).

[0125] In addition, the multi-core optical cable (100) according to the present invention may have an identification portion (31) such as a protrusion or stripe formed in a region corresponding to the position where the notch portion (n) is formed among the outer peripheral area of ​​the cable jacket (30). The protrusion may be formed in a shape that protrudes radially from the outer peripheral area of ​​the cable jacket (30) by being connected to the outer peripheral area of ​​the cable jacket (30).

[0126] The above identification part (31) enables external identification of which area of ​​the inner surface of the cable jacket (30) the notch part (n) is formed in without directly opening the inside by removing the cable jacket (30).

[0127] In this way, the multi-core optical cable (100) according to the present invention is provided with an identification portion (31), so that when a worker cuts the cable jacket (30) in the area where the identification portion (31) is located during a stripping operation of the cable jacket (30), the notch portion (n) formed on the inner surface of the cable jacket (30) is opened, and the core (C) or ripcord (50) arranged in the empty space inside the notch portion (n) can be exposed without being damaged.

[0128] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. A plurality of optical units comprising a plurality of optical fibers and a plurality of waterproof yarns; and a bundle member that collects the plurality of optical fibers and the plurality of waterproof yarns; and A cable jacket surrounding the above plurality of optical units; The bundle member of the above optical unit can be shaped differently to correspond to the shape of the space arranged inside the cable jacket. A multi-core optical cable characterized in that the moisture absorption rate per minute of the entire waterproof yarn accommodated in each of the above optical units is 18 g / m or more.

2. In paragraph 1, A multi-core optical cable characterized in that the plurality of optical fibers are accommodated in the bundle member in the form of a plurality of rollable optical fiber ribbons.

3. In paragraph 1, A multi-core optical cable, characterized in that the shortest distance between any one of the plurality of waterproof yarns accommodated inside the bundle member of the optical unit and the optical fiber located closest to the waterproof yarn is less than or equal to four times the diameter of the optical fiber.

4. In paragraph 1, A multi-core optical cable, characterized in that one waterproof yarn and two adjacent waterproof yarns among the plurality of waterproof yarns accommodated inside the bundle member of the optical unit do not simultaneously contact each other at the same point in the longitudinal direction of the optical cable.

5. In paragraph 1, A multi-core optical cable characterized in that the internal cable space factor according to the following [Formula 1] is in the range of 55% to 85%. [Formula 1] Cable internal space factor (%) = (Total cross-sectional area of ​​optical fibers accommodated in the optical cable) / (Internal cross-sectional area of ​​cable jacket) * 100 (%) 6. In paragraph 1, A multi-core optical cable characterized in that 10 to 19 waterproof yarns are provided inside the bundle member of the optical unit.

7. In paragraph 1, A multi-core optical cable characterized in that 20 to 30 waterproof yarns are provided inside the bundle member of the optical unit.

8. In paragraph 5, A multi-core optical cable characterized in that the moisture absorption rate of each waterproof yarn accommodated inside the bundle member of the optical unit is 1 g / m or more per minute.

9. In paragraph 5, A multi-core optical cable characterized in that the largest value among the internal dot ratios of the optical unit according to the following [Formula 2] is 1.05 to 2 times the smallest value of the internal dot ratio of the optical unit. [Formula 2] Optical unit internal space factor (%) = (Total cross-sectional area of ​​optical fibers accommodated in bundle member) / (Internal cross-sectional area of ​​bundle member) * 100 (%) 10. In paragraph 9, A multi-core optical cable characterized in that the largest value among the internal dot ratios of the optical unit according to the above [Formula 2] is 1.05 to 1.6 times the smallest value of the internal dot ratio of the optical unit.

11. In paragraph 1, A multi-core optical cable, characterized in that the total thickness of the plurality of waterproof yarns accommodated inside the bundle member of the optical unit is in the range of 11,000 denier to 26,000 denier.

12. In paragraph 11, A multi-core optical cable, characterized in that the thickness of each waterproof yarn inside the bundle member of the optical unit is in the range of 500 denier to 2500 denier.

13. In paragraph 1, A multi-core optical cable characterized in that the above waterproof yarn is coated with a super absorbent polymer (SAP) in powder form.

14. In paragraph 13, A multi-core optical cable characterized in that the above-mentioned highly absorbent waterproof material changes into a jelly or gel form when in contact with moisture, thereby providing a waterproof function.

15. In paragraph 1, A multi-core optical cable characterized in that 70 to 199 optical fibers are provided inside the bundle member of the optical unit.

16. In paragraph 1, A multi-core optical cable characterized in that 200 to 300 optical fibers are provided inside the bundle member of the optical unit.

17. In paragraph 1, A multi-core optical cable characterized in that 10 to 19 optical units are provided inside the cable jacket.

18. In paragraph 1, A multi-core optical cable characterized in that 20 to 30 optical units are provided inside the cable jacket.

19. In paragraph 1, A multi-core optical cable characterized in that it further includes a binding member that wraps the outer side of the plurality of optical units on the inner surface of the cable jacket.

20. In paragraph 1, A multi-core optical cable characterized in that it further includes a plurality of tension members embedded in the length direction of the cable inside the cable jacket.

21. In paragraph 20, A multi-core optical cable, characterized in that the plurality of tension members include a pair of tension members each arranged adjacent to each other at positions symmetrical to each other with respect to the center of the optical cable.

22. In paragraph 1, A multi-core optical cable characterized in that at least one notch is formed on the inside of the cable jacket, and a rip cord is provided in the space inside the notch.

23. In paragraph 22, A multi-core optical cable characterized in that a protrusion is formed in an area corresponding to the position where the notch is formed among the outer peripheral area of ​​the cable jacket.

24. In paragraph 1, A multi-core optical cable, characterized in that the overall outer diameter of the multi-core optical cable is in the range of 25 millimeters to 40 millimeters (mm).

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