Covered optical cables are mostly single-core and double-core structures, and can also be made into four-core structures. The cross-section is 8-shaped, and the reinforcement is located at the center of the two circles. Metal or non-metallic structures can be used. The optical fiber is located at the geometric center of the 8-shaped. . The optical fiber in the sheathed cable uses G.657 small bending radius optical fiber, which can be laid with a bending radius of 20mm, which is suitable for entering the house in the building by means of pipes or bright wires.
Leather cable is commonly known as indoor suspended wiring optical cable. With the domestic optical fiber access market showing a good momentum of development, optical fiber access has become a hot spot in the field of optical communications. In the optical fiber access project, indoor wiring close to the user is the most complicated link. The bending performance and tensile performance of conventional indoor optical cables can no longer meet the requirements of FTTH (fiber to the home) indoor wiring.
The dish-shaped drop optical cable for the access network (for indoor wiring) is to place the optical communication unit (optical fiber) in the center, and place two parallel non-metallic reinforcements (FRP) or metal reinforcements on both sides. Finally, extruded black or colored poly Vinyl chloride (PVC) or low-smoke halogen-free material (LSZH, low-smoke, halogen-free, flame retardant) sheathed
Features
Special bending-resistant optical fiber provides greater bandwidth and enhances network transmission performance;
Two parallel FRP or metal reinforcements make the optical cable have good compression resistance and protect the optical fiber;
The optical cable has simple structure, light weight and strong practicability;
Unique groove design, easy to peel, convenient to connect, simplify installation and maintenance;
Low-smoke halogen-free flame-retardant polyethylene sheath or flame-retardant PVC sheath, environmentally friendly.
It can be matched with a variety of on-site connectors and can be completed on-site.
Because of its softness and lightness, the drop cable is widely used in the access network; the scientific name of the drop cable: the butterfly-shaped lead-in cable for the access network; because its shape is butterfly-shaped; it is also called butterfly-shaped optical cable, Figure 8 Optical Cable
product structure
The ordinary sheathed optical cable is a standard figure-eight structure; two parallel reinforced cores with an optical fiber in the middle; the self-supporting sheathed optical cable adds a thick steel wire suspension wire to the structure of the ordinary sheathed optical cable; in general, the self-supporting sheath The optical fiber cable is just one more steel wire, and the others remain unchanged;
The structure of each manufacturer of this type of optical cable is different. But it is generally not a metal reinforced core, take the butterfly-shaped sheathed optical cable as an example. The cross-section looks like a butterfly, so it is called. On both sides, there are stiffeners inside the leather wire, and the middle part is an optical fiber.
1. Butterfly-shaped optical cables are divided into indoor and indoor (inside) and outdoor. The price difference between the two is quite large. The price of outdoor type is about twice the price of indoor type. The price factor should be considered when making specific design plans. Generally speaking, Ordinary fiber optic cable (GYTA-G 652D) is still used outdoors, and indoor butterfly fiber optic cables are used indoors, and the two are transitioned through fiber splitting boxes or splice boxes.
2. The butterfly-shaped optical cable has a small radius of curvature, light weight, relatively good bending resistance, easy to fix, and easy to terminate in the 86 terminal box.
3. The butterfly-shaped home optical cable has two forms: non-metallic strengthening member and metal strengthening member. Taking into account the factors of lightning protection and strong electric interference, the non-metallic strengthening member butterfly optical cable should be used indoors.
4. Indoor butterfly optical cables have specifications such as 1 core, 2 cores, 3 cores, 4 cores, etc. Single core cable should be used for residential users to access butterfly optical fiber cables; for business users to access butterfly optical cables, press 2--4 Core cable design.
There are cold splicing and welding.
Cold splicing is to install the terminal by preparing the end face of the optical fiber and connect it with the flange head.
Applications
For indoor wiring, end users directly use cables;
Used for building optical fiber drop cables;
It is used for indoor wiring of users in FTTH.
Construction method
In the large-scale use of leather fiber optic cables in FTTX projects, two splicing methods are mainly used: one is optical cable cold splicing technology (physical splicing) based on cold splicing, and the thermal fusion technology using fusion splicer as a tool.
Cold joint technology
Cold splicing technology: The optical fiber cold splice is used when two pigtails are butted. The main component inside is a precision v-groove. After the two pigtails are pulled out, the cold splice is used to realize the butt of the two pigtails. The operation is simpler and faster, and it saves time than using a fusion splicer.
On the surface, the cold splicing operation is simple and fast, which saves time compared to the hot melt of the fusion splicer. However, the cold splicing technology is mainly used in emergency applications after the optical cable communication is interrupted.
The cold joint technology has obvious defects:
(1) The cold connection loss is large. Due to the use of physical connection, the two optical fibers are completely connected by V-groove and matching liquid, so the loss is obviously greater than that of the hot-melt connection point. In the FTTX project, although the line loss requirements are not as strict as the trunk line requirements, the large loss point is the potential failure point.
(2) The service life is short and the maintenance cost is high. In cold junction technology, the role of matching fluid is very important. Quoting the statistics of the operator’s customers, the imported matching fluid generally has a life span of about 3 years, while the domestic matching fluid has a life span of only 1.5 to 2 years. In this way, the cost of maintenance is increased. Moreover, the cost of a cold splice is generally about 30 to 50 yuan (it can be disassembled and reused, but the accuracy of reuse after disassembly is greatly reduced, so the cold splice is nominally repeatable, but it is actually used in the construction process. Only used once), the actual use and maintenance cost is high.
Hot melt technology
1. The splicing loss is small. The two optical fibers are fusion spliced in accordance with the trunk line standard using hot-melt technology, which greatly reduces splicing loss.
2. Long service life and low maintenance cost. Since the hot-melt standard is required for the construction of the main line, the life of the general welding point will be similar to the life of the ordinary optical cable, and there is no single point life problem.
Home method
User indoor wiring
In the FTTH project, the user's indoor wiring is the most complicated link, and many factors are considered. It is necessary to ensure the safety of the circuit, while taking into account the beauty of the interior, as well as the convenience of construction. The traditional single-core indoor optical cable can no longer meet the requirements of the indoor wiring of the FTTH project at this stage. As a substitute for traditional indoor optical cables, Weipuxun leather cable can adapt to most indoor wiring conditions, for example, it can turn with a bending radius of 20mm, can bear the side pressure of people stepping on the optical cable, and the drag caused by engineering construction pull. At the same time, with a variety of field connectors, field termination and docking can be realized in the shortest time. Therefore, Weipuxun leather cable is the best choice for FTTH indoor wiring.
Vertical and horizontal wiring inside the building
Like the indoor wiring of users, VIPXun cable is also suitable for vertical and horizontal wiring in buildings. Horizontal cabling is not very demanding for optical cables, but vertical cabling must require optical cables to have a certain degree of tensile performance. Weipuxun leather cable can withstand a maximum tensile force of 200 Newtons for short-term and 100 Newtons for long-term, so it can ensure the safety and stable performance of the vertical wiring of the leather cable within a certain height range.
Self-supporting overhead home wiring
Since the self-supporting "8" wiring optical cable has a metal suspension wire unit, it has stronger tensile performance and can withstand a span of 50 meters. The optical cable is laid in an overhead manner outdoors, the metal hanging wire unit is cut off before entering the house and fixed on a special holder, and the remaining optical cable is stripped of the metal hanging wire and introduced into the room with a leather cable.
Pipeline home wiring
Since the pipe-mapped optical cable is harder and has higher tensile strength than the sheathed optical cable, and the optical cable contains water-blocking materials, which can reduce outdoor rain erosion, it is more suitable for long-distance outdoor pipeline laying. Weipuxun pipeline mapping optical cable adopts all non-metallic structure, thus avoiding the entry of lightning into the room. After the fiber optic cable enters the house, the outer sheath, water blocking materials and reinforcements are stripped, and the inner sheathed fiber optic cable is directly used for indoor wiring, which inherits all the advantages of the sheathed fiber optic cable indoor wiring, and reduces the link of outdoor and indoor fiber optic cable splicing.
