CN114185139B

CN114185139B - Optical cable

Info

Publication number: CN114185139B
Application number: CN202210092424.XA
Authority: CN
Inventors: 朱卫华; 王新新; 魏成东; 杨晓; 唐毅
Original assignee: Sichuan Tianfu Jiangdong Technology Co ltd; Jiangsu Zhongtian Technology Co Ltd
Current assignee: Sichuan Tianfu Jiangdong Technology Co ltd; Jiangsu Zhongtian Technology Co Ltd
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2024-06-28
Anticipated expiration: 2042-01-26
Also published as: CN114185139A

Abstract

The invention provides an optical cable which comprises a plurality of optical fiber units and a first protective layer, wherein the optical fiber units are arranged in the first protective layer in a penetrating manner, and water blocking pieces are filled in the first protective layer; the optical fiber unit comprises a reinforcing wire harness, a plurality of optical fibers and a second protective layer, wherein the optical fibers and the reinforcing wire harness extend along the length direction of the optical cable, the optical fibers comprise an optical fiber body and a first flame-retardant layer, the first flame-retardant layer is coated on the outer wall surface of the optical fiber body, the optical fibers are positioned in the reinforcing wire harness, and the second protective layer is coated on the outer side of the reinforcing wire harness. The optical cable provided by the invention can effectively protect the optical fiber.

Description

Optical cable

Technical Field

The invention relates to the technical field of communication optical cables, in particular to an optical cable.

Background

The optical cable is widely applied to the field of communication as a transmission medium, for example, the optical cable can be applied to places such as communication machine rooms, data centers, mines, nuclear power facilities, high-rise buildings, airports, subways and the like. Correspondingly, the fire-retardant and fire-resistant performance of the optical cable under the condition of fire disaster is required to be high.

In the prior art, the optical cable comprises an armor layer and a plurality of optical fiber units penetrating through the armor layer, wherein the optical fiber units are arranged in parallel, and each optical fiber unit comprises a loose tube, an optical fiber arranged in the loose tube and a water blocking yarn. Wherein, the optical fiber is loosely arranged in the loose tube so as to reserve the expansion space of the water-blocking yarn.

However, when the optical cable encounters fire, the loose tube can be deformed by heat, so that the optical fiber is deformed, then the loose tube is abutted to generate tensile or compressive bending damage, the water-blocking yarn can burn when encountering fire, the optical fiber can be burnt, and the optical cable has the hidden trouble of communication interruption.

Disclosure of Invention

In view of the foregoing, embodiments of the present invention provide an optical cable that can form an effective protection for an optical fiber.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

The embodiment of the invention provides an optical cable, which comprises a plurality of optical fiber units and a first protective layer, wherein the optical fiber units are arranged in the first protective layer in a penetrating way, and water blocking pieces are filled in the first protective layer; the optical fiber unit comprises a reinforcing wire harness, a plurality of optical fibers and a second protective sleeve, wherein the optical fibers and the reinforcing wire harness extend along the length direction of the optical cable, the optical fibers comprise an optical fiber body and a first flame-retardant layer, the first flame-retardant layer is coated on the outer wall surface of the optical fiber body, the optical fibers are positioned in the reinforcing wire harness, and the second protective layer is coated on the outer side of the reinforcing wire harness.

In some possible embodiments, the reinforcement strands include a plurality of first reinforcement yarns, the first reinforcement yarns being aramid yarns or fiberglass yarns.

In some possible embodiments, the material of the first flame retardant layer is flame retardant polyimide, flame retardant polyolefin, flame retardant polyester or flame retardant polyurethane.

In some possible embodiments, the reinforcement harness and the plurality of optical fibers are configured to be stranded around an axis of the optical fiber unit.

In some possible embodiments, a plurality of the optical fibers are arranged at intervals along the circumferential direction of the optical fiber unit.

In some possible embodiments, the fiber optic cable further comprises a plurality of second strength yarns embedded within the wall of the second protective layer; the second reinforcing yarns are aramid yarns, glass fiber yarns, steel wires or steel strands.

In some possible embodiments, the first protective layer includes an armor steel band surrounding the outer sides of the plurality of optical fiber units and a wire braid wrapping the outer sides of the armor steel band.

In some possible embodiments, the first protective layer further comprises a second flame retardant layer and a third flame retardant layer, the armor steel tape is coated on the outer side of the second flame retardant layer, and the third flame retardant layer is coated on the outer side of the steel wire braiding layer; wherein the material of the second flame-retardant layer is flame-retardant polyimide, flame-retardant polyolefin, flame-retardant polyester or flame-retardant polyurethane; the third flame-retardant layer is made of flame-retardant polyimide, flame-retardant polyolefin, flame-retardant polyester or flame-retardant polyurethane.

In some possible embodiments, the water blocking member is a water blocking yarn, a water blocking ointment, a water blocking powder, or a water blocking resin.

In some possible embodiments, the optical cable further comprises a central strength member extending along a length of the optical cable, the plurality of optical fiber units being configured to be stranded outside the central strength member.

Compared with the prior art, the optical cable provided by the embodiment of the invention has the following advantages: by filling the water blocking member in the first protective layer, the circulation of moisture in the longitudinal direction of the optical cable can be avoided. Through cladding first fire-retardant layer in the outside of optic fibre body, can form the protection to the optic fibre body when the optical cable meets the fire, avoid the optic fibre body to meet the fire damage. And through setting up optic fibre in strengthening the pencil, and outside strengthening the pencil with second inoxidizing coating cladding, can make strengthening the pencil and constitute comparatively dense entity structure, optic fibre is located this entity structure, and the second inoxidizing coating cladding is on the outer wall surface of this entity structure. Therefore, even if the second protective layer breaks and deforms when meeting fire, the solid structure also has a stable shape so as to avoid the optical fiber body from being damaged due to the abutting of the second protective layer. That is, the optical cable can effectively protect the optical fiber body, and avoid the communication interruption caused by the fire of the optical cable.

In addition to the technical problems, technical features constituting the technical solutions, and beneficial effects caused by the technical features of the technical solutions described above, other technical problems that the optical cable provided by the embodiment of the present invention can solve, other technical features included in the technical solutions, and beneficial effects caused by the technical features of the technical solutions, further detailed description will be made in the detailed description of the present invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an optical cable according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the optical fiber unit of FIG. 1;

fig. 3 is a schematic structural view of the optical fiber in fig. 2.

Reference numerals:

100: an optical cable;

110: an optical fiber unit;

111: reinforcing the wire harness;

112: an optical fiber;

1121: an optical fiber body;

1122: a first flame retardant layer;

1123: a coloring layer;

113: a second protective layer;

120: a first protective layer;

121: armoured steel strip;

122: a steel wire braiding layer;

123: a second flame retardant layer;

124: a third flame retardant layer;

130: a second reinforcing yarn;

140: a water blocking member;

150: a central reinforcement;

160: and a supplement.

Detailed Description

In order to make the above objects, features and advantages of the embodiments of the present invention more comprehensible, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the prior art, the optical fibers are loosely arranged in the loose tube, namely the optical fibers have a movable space, and the loose tube is also filled with water-blocking yarns for preventing water from flowing along the length direction of the optical cable. However, when the optical cable encounters fire, the loose tube is broken and deformed, and the water-blocking yarn is burnt when encountering air, so that the optical fiber is not only damaged by bending under tension or compression due to the abutting of the deformed loose tube, even broken, but also burnt due to the burning of the water-blocking yarn, and the optical cable has hidden danger of communication interruption, that is, the optical cable in the prior art cannot provide effective protection for the optical fiber.

In view of the foregoing, an embodiment of the present application provides an optical cable, where the optical cable includes a plurality of optical fiber units and a first protection layer, the optical fiber units are disposed in the first protection layer in a penetrating manner, and a water blocking member is further filled in the first protection layer to prevent moisture from flowing along a length direction of the optical cable.

Each optical fiber unit comprises an optical fiber body and a first flame-retardant layer, so that the optical fiber body can be protected through the first flame-retardant layer, and the optical fiber body is prevented from being burnt when encountering fire. Meanwhile, the reinforced wire harness and the optical fiber units form a compact solid structure, and the second protective layer of the optical fiber units is coated on the outer wall surface of the solid structure, so that even if the second protective layer is heated, broken and deformed, the shape of the solid structure is less influenced by the second protective layer, and bending damage caused by tension or compression due to the abutting of the deformed second protective layer can be avoided, namely, the optical cable can form effective protection for the optical fiber body, and communication interruption caused by fire of the optical cable is avoided.

Fig. 1 is a schematic structural diagram of an optical cable according to an embodiment of the present invention. Fig. 2 is a schematic structural view of the optical fiber unit in fig. 1. Fig. 3 is a schematic structural view of the optical fiber in fig. 2.

Referring to fig. 1 to 3, the present embodiment provides an optical cable 100, which includes a plurality of optical fiber units 110 and a first protection layer 120, wherein the plurality of optical fiber units 110 are disposed in the first protection layer 120 in a penetrating manner, and a water blocking member 140 is further filled in the first protection layer 120, that is, the water blocking member 140 is filled in a gap between two adjacent optical fiber units 110, so as to achieve a longitudinal water blocking effect of the optical fiber 112. In some possible embodiments, the water blocking member 140 is a water blocking yarn, a water blocking ointment, a water blocking powder, or a water blocking resin, and the present embodiment does not limit the kind of the water blocking member 140.

When the water blocking member 140 is a water blocking yarn, the water blocking yarn includes two parts, one part is an expansion fiber or an expansion powder containing polyacrylate, and expands after absorbing water to realize the longitudinal water blocking effect of the optical cable 100, and the other part is a reinforcing rib made of nylon or polyester, so that the water blocking yarn has preset tensile strength and extensibility.

When water blocking member 140 is a water blocking ointment, the water blocking ointment may be a water-swellable water blocking ointment or a heat-swellable water blocking ointment, which are well known to those skilled in the art.

When the water blocking member 140 is a water blocking powder, the water blocking powder may be a high molecular water absorbent resin (SAP) powder, such as starch, polyacrylate powder, etc.

When the water blocking member 140 is a water blocking resin, the water blocking resin may be Polyethylene (PE), polypropylene (PP).

In some embodiments, referring to fig. 2, the optical fiber unit 110 includes a plurality of optical fibers 112, where at least one optical fiber 112, for example, 1-20 optical fibers 112. When the number of the optical fibers 112 is plural, the plural optical fibers 112 may be disposed at intervals around the circumference of the optical fiber unit 110.

Referring to fig. 3, the optical fiber 112 includes an optical fiber body 1121 and a first flame retardant layer 1122, and the first flame retardant layer 1122 is coated on an outer wall surface of the optical fiber body 1121. The first flame-retardant layer 1122 has a flame-retardant effect, so that when the optical cable 100 burns on fire, the optical fiber body 1121 can be protected by the first flame-retardant layer 1122, and the conditions of thermal burn of the optical fiber body 1121 and communication interruption of the optical cable 100 are avoided.

In some embodiments, to facilitate distinguishing the optical fibers 112, the outer side of the first flame retardant layer 1122 is further coated with a colored layer 1123, and different types of optical fibers 112 may be provided with different colors, such as red, yellow, blue, purple, etc. The colored layer 1123 may be coated on the outside of the first flame retardant layer 1122 by Ultraviolet (UV) curing.

In some possible embodiments, the material of the first flame retardant layer 1122 is flame retardant polyimide, flame retardant polyolefin, flame retardant polyester or flame retardant polyurethane, which has a better flame retardant effect.

The material of the first flame retardant layer 1122 is exemplified as flame retardant polyolefin, and when the optical cable 100 burns with fire, the first flame retardant layer 1122 can be hardened into a ceramic tubular structure and coated on the outer wall surface of the optical fiber body 1121, so as to avoid the optical fiber body 1121 from being burnt with flame, meanwhile, the hardness of the ceramic tubular first flame retardant layer 1122 is higher, the ceramic tubular first flame retardant layer 1122 can resist the deformation of the second protective layer 113, so as to protect the optical fiber body 1121 inside the ceramic tubular first flame retardant layer 1122, and avoid the bending deformation of the optical fiber body 1121 caused by tension or compression, and also avoid the conditions of breakage and communication interruption of the optical fiber body 1121 when the optical cable 100 burns.

To form an effective protection for the optical fibers 112, in some embodiments, the optical fiber unit 110 further includes a reinforcing wire harness 111 and a second protection layer 113, where the optical fibers 112 and the reinforcing wire harness 111 extend along the length direction of the optical cable 100, and the optical fibers 112 are located in the reinforcing wire harness 111, so that the reinforcing wire harness 111 and the plurality of optical fibers 112 form a dense solid structure, and the second protection layer 113 is wrapped on the outer side of the reinforcing wire harness 111, that is, the second protection layer 113 is wrapped on the outer wall surface of the solid structure.

The physical structure has higher structural stability, that is, the physical structure has a relatively stable appearance, so that even if the second protective layer 113 breaks and deforms, the physical structure will not deform under the influence of the deformed second protective layer 113, that is, even if the optical cable 100 burns on fire, the optical fiber 112 can still be maintained in an initial state approximately, and the optical fiber unit 110 is prevented from bending and deformation caused by tension or compression due to the breaking and deformation of the second protective layer 113, and the interruption of the communication of the optical cable 100 is avoided.

Thus, by coating the first flame retardant layer 1122 on the outer side of the optical fiber body 1121, the optical fiber body 1121 can be protected from being burned when the optical cable 100 burns on fire. And by arranging the reinforcing wire harness 111 and arranging the optical fibers 112 in the reinforcing wire harness 111, the reinforcing wire harness 111 and the optical fibers 112 can form a compact solid structure, and the solid structure is less affected by the deformed second protective layer 113, so that bending damage of the optical fiber body 1121 caused by tension or compression is avoided. That is, the optical cable 100 provided in this embodiment has better flame retardant and fire resistant properties, and can form effective protection for the optical fiber body 1121, so as to avoid communication interruption when the optical cable 100 burns on fire.

In some possible embodiments, the reinforcing strands 111 include a plurality of first reinforcing yarns (not shown) that are aramid yarns or fiberglass yarns.

The aramid yarn has the advantages of low density, high tensile modulus and high breaking strength, and meanwhile, the shrinkage rate of the aramid yarn at a high temperature is low, namely the flame retardance and the fire resistance of the aramid yarn are high. The glass fiber yarn has better heat resistance and corrosion resistance, and the tensile strength of the glass fiber yarn is higher.

In this way, the first reinforcing yarns are aramid yarns or glass yarns, and the reinforcing strands 111 can still be maintained approximately in the original state when the optical cable 100 is burned upon fire.

The wire diameter of the aramid yarn or the glass fiber yarn may be determined according to the diameter of the optical cable 100. For example, the aramid yarn may be 30-400TeX (TeX, simply "TeX"), which refers to the weight grams of a fiber or yarn 1000 meters long at a nominal moisture regain.

Wherein, the stability of the solid structure can be improved by binding the reinforcing wire harness 111, so as to avoid the scattering of the reinforcing wire harness 111 after the second protective layer 113 is broken and deformed.

In some possible embodiments, the reinforcement wire harness 111 and the plurality of optical fibers 112 are configured to be stranded around an axis of the optical fiber unit 110. Wherein the twist pitch may be set as desired.

In this way, the plurality of first reinforcing yarns and the plurality of optical fibers 112 are twisted into one body, which has a deformation resistance capable of resisting the deformation of the second protective layer 113, so that the plurality of first reinforcing yarns and the plurality of optical fibers 112 can be maintained as one body even if the second protective layer 113 breaks, so as to avoid bending deformation of the optical fibers 112 in tension or compression.

In order to protect the optical fibers 112, the optical fibers 112 are disposed inside the reinforcing wire harness 111, that is, the outer periphery of the optical fibers 112 is provided with first reinforcing yarns.

Wherein, two adjacent optical fibers 112 may be disposed adjacently, that is, two adjacent optical fibers 112 abut against each other.

In some possible embodiments, the optical fibers 112 may also be disposed at intervals to avoid abrasion between the optical fibers 112, for example, the optical fibers 112 may be disposed at intervals along the circumference of the optical fiber unit 110. In this way, the optical fiber unit 110 can be formed into a relatively round linear structure.

To increase the strength of the second protective layer 113, referring to fig. 2, in some possible embodiments, the optical fiber cable 100 further includes a plurality of second reinforcing yarns 130, where the second reinforcing yarns 130 are embedded in the wall of the second protective layer 113, and the second reinforcing yarns 130 may extend along the length direction of the second protective layer 113 or may extend spirally around the circumference of the second protective layer 113. The number of the second reinforcing yarns 130 may be plural, and the plural second reinforcing yarns 130 are disposed at intervals along the circumferential direction of the second protective layer 113.

The second reinforcing yarns 130 may be non-metallic members, for example, the second reinforcing yarns 130 are aramid yarns or fiberglass yarns. The aramid yarn has the advantages of low density, high tensile modulus and high breaking strength, and meanwhile, the shrinkage rate of the aramid yarn at a high temperature is low, namely the flame retardance and the fire resistance of the aramid yarn are high. The glass fiber yarn has better heat resistance and corrosion resistance, and the tensile strength of the glass fiber yarn is higher.

The second reinforcing yarn 130 may also be a metal piece with high strength. For example, the second reinforcing yarns 130 are steel wires or strands.

In some possible embodiments, referring to fig. 1, the first protective layer 120 includes an armor tape 121, and the armor tape 121 is disposed around the outside of the plurality of optical fiber units 110. The armor steel tape 121 may be longitudinally wrapped around the outer sides of the plurality of optical fiber units 110, so that the assembly efficiency of the optical cable 100 is high.

The overlapping position of the armor tape 121 may be filled with an ointment to avoid gaps at the overlapping position of the armor tape 121. In some embodiments, the overlapping position of the armor tape 121 may also be fixed by welding, or by wrapping steel wire around the outside of the armor tape 121.

In some embodiments, the first protective layer 120 further comprises a wire braid 122, the wire braid 122 being wrapped around the outside of the armor tape 121. Thus, the steel wire braid 122 can limit the position of the armor steel belt 121 so as to prevent the overlap joint position of the armor steel belt 121 from cracking when the optical cable 100 encounters fire, thereby causing the inside of the optical cable 100 to burn.

The steel wire braid 122 is formed by weaving steel wires, and the weaving lines of the steel wire braid 122 are not limited in this embodiment. The diameter of the steel wire may be 0.1mm-1mm and the braiding coefficient of the steel wire braiding layer 122 may be 0.3-0.8. It should be noted that, the numerical values and the numerical ranges related to the embodiments of the present application are approximate values, and may have a certain range of errors under the influence of the manufacturing process, and those errors may be considered to be negligible by those skilled in the art.

In some possible embodiments, referring to fig. 1, the first protective layer 120 further includes a second flame retardant layer 123 and a third flame retardant layer 124, the armor tape 121 is coated on the outer side of the second flame retardant layer 123, and the third flame retardant layer 124 is coated on the outer side of the steel wire braid 122, so as to improve the flame retardant performance of the optical cable 100.

Wherein, the material of the second flame retardant layer 123 is flame retardant polyimide, flame retardant polyolefin, flame retardant polyester or flame retardant polyurethane; the third flame retardant layer 124 is made of flame retardant polyimide, flame retardant polyolefin, flame retardant polyester or flame retardant polyurethane. The materials of the second flame retardant layer 123 and the third flame retardant layer 124 may be the same or different. For example, the materials of the second flame retardant layer 123 and the third flame retardant layer 124 are flame retardant polyolefin.

When the materials of the second flame retardant layer 123 and the third flame retardant layer 124 are both flame retardant polyolefin, the flame retardant polyolefin may be hardened into a ceramic tubular structure to prevent the optical fiber unit 110 inside the optical cable 100 from being burned by heat. Meanwhile, the ceramic tubular structure has higher hardness, so that the inner optical fiber unit 110 can be protected, bending deformation of the optical fiber unit 110 caused by tension or compression is avoided, and the conditions of breakage and communication interruption of the optical fiber unit 110 during the combustion of the optical cable 100 can be avoided.

In some possible embodiments, cable 100 further includes a center strength member 150, the cross-sectional shape of center strength member 150 may be rectangular, circular, oval, or other shape, the cross-sectional dimension of center strength member 150 may be greater than or less than the outer diameter of fiber unit 110, or the outer diameter of center strength member 150 may be comparable to the outer diameter of fiber unit 110.

Wherein the center strength member 150 extends along the length of the optical cable 100, and the plurality of optical fiber units 110 are configured to be stranded outside the center strength member 150. In this way, the center strength member 150 and the plurality of optical fiber units 110 can be connected as a unit, the strength of the optical cable 100 is high, and the roundness of the optical cable 100 is high.

In some embodiments, the center strength member 150 may be a non-metallic member to reduce the weight of the fiber optic cable 100. For example, the center reinforcement 150 is made of fiberglass, basalt, or the like.

In some embodiments, the center reinforcement 150 may also be a metal piece, such as steel, for example, with a higher strength center reinforcement 150.

In some embodiments, when the number of the plurality of optical fiber units 110 is insufficient to wind the central strength member 150 for one round, for example, the optical cable 100 in fig. 1 is provided with four optical fiber units 110, in this case, a supplement 160 may be further disposed in the first protective layer 120, and an outer diameter of the supplement 160 may be equal to an outer diameter of the optical fiber units 110, where the supplement 160 is twisted together with the plurality of optical fiber units 110 on the central strength member 150.

Wherein the supplemental member 160 may be a non-metallic member to reduce the weight of the fiber optic cable 100. For example, the material of the replenishment 160 is fiberglass, basalt, or the like. The supplement 160 may also be a metal member, such as steel, etc., and the supplement 160 may have a high strength.

In some embodiments, the fiber optic cable 100 is formed as follows:

molding the optical fiber 112: a first flame retardant layer 1122 is formed on the outside of the optical fiber body 1121, and then a colored layer 1123 is formed on the outside of the first flame retardant layer 1122.

The optical fiber unit 110 is molded: the plurality of optical fibers 112 are stranded with the reinforcing strands 111 and then extruded to form the second protective layer 113.

And (3) cable core forming: the plurality of optical fiber units 110 are stranded with the center reinforcement 150.

And forming a second flame retardant layer 123: the second flame retardant layer 123 may be formed by extrusion molding.

The armor tape 121 and the wire braid 122 are coated.

Third flame retardant layer 124 is molded: the third flame retardant layer 124 may be formed by extrusion.

In this specification, each embodiment or implementation is described in a progressive manner, and each embodiment focuses on a difference from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. An optical cable, characterized by comprising a plurality of optical fiber units, a first protective layer, a central reinforcing member and a plurality of second reinforcing yarns, wherein the optical fiber units are arranged in the first protective layer in a penetrating manner, the first protective layer is also filled with a water blocking member and a supplementing member, the central reinforcing member extends along the length direction of the optical cable, the optical fiber units are configured to be stranded outside the central reinforcing member, the external diameter of the supplementing member is equal to the external diameter of the optical fiber units, and the supplementing member and the optical fiber units are stranded on the central reinforcing member together;

The optical fiber unit comprises a reinforcing wire harness, a plurality of optical fibers and a second protective layer, wherein the optical fibers and the reinforcing wire harness extend along the length direction of the optical cable, the optical fibers comprise an optical fiber body and a first flame-retardant layer, the first flame-retardant layer is coated on the outer wall surface of the optical fiber body, the optical fibers are positioned in the reinforcing wire harness, and the second protective layer is coated on the outer side of the reinforcing wire harness; wherein the first flame retardant layer hardens into a ceramic tubular structure when burned;

the second reinforcing yarns are embedded in the pipe wall of the second protective layer.

2. The fiber optic cable of claim 1, wherein the strength strand includes a plurality of first strength yarns, the first strength yarns being aramid yarns or fiberglass yarns.

3. The fiber optic cable of claim 1, wherein the first flame retardant layer is a flame retardant polyimide, a flame retardant polyolefin, a flame retardant polyester, or a flame retardant polyurethane.

4. The fiber optic cable of claim 1, wherein the strength strand and the plurality of optical fibers are configured to be stranded about an axis of the optical fiber unit.

5. The fiber optic cable of claim 1, wherein a plurality of the optical fibers are disposed at intervals along a circumferential direction of the optical fiber unit.

6. The fiber optic cable of claims 1-5, wherein,

The second reinforcing yarns are aramid yarns, glass fiber yarns, steel wires or steel strands.

7. The fiber optic cable of claims 1-5, wherein the first protective layer includes an armor tape surrounding an outer side of the plurality of fiber optic units and a wire braid surrounding the armor tape.

8. The fiber optic cable of claim 7, wherein the first protective layer further comprises a second flame retardant layer and a third flame retardant layer, the armor tape being wrapped outside the second flame retardant layer, the third flame retardant layer being wrapped outside the wire braid;

Wherein the material of the second flame-retardant layer is flame-retardant polyimide, flame-retardant polyolefin, flame-retardant polyester or flame-retardant polyurethane; the third flame-retardant layer is made of flame-retardant polyimide, flame-retardant polyolefin, flame-retardant polyester or flame-retardant polyurethane.

9. The fiber optic cable of claims 1-5, wherein,

The water-blocking piece is water-blocking yarn, water-blocking ointment, water-blocking powder or water-blocking resin.