Three kinds of fiber-optic cable laying methods

At present, outdoor optical cables for core networks and access networks for communications have a relatively mature structure and a laying method suitable for China's national conditions. At the same time, after the development in recent years, the indoor optical cable also has a relatively mature structure and has sufficient production capacity. However, this section of the optical cable line entering the home of the communication network is partly outdoors and partly indoors, which puts forward new requirements on the requirements of the optical cable and its laying methods. The requirements for fiber capacity in these locations will continue to grow, but there are still rules to follow, and everything will depend on the needs of users. Fiber optic cables are pre-placed in places where there is potential demand, obviously there will be a waste and a backlog of funds. At the same time, the route that the optical cable line entering the communication network will go through may already be a shaped park. It will be difficult to rebuild large communication pipelines here. A large number of overhead installations will not only damage the beautiful landscape environment, but also the lines are not safe.

In order to solve these demand problems, products adapted to new laying methods have been released. At present, there are three main types of new cable laying methods at home and abroad: one is to blow micro-cables or optical fiber bundles and optical fiber units into pre-laid micro-tubes using air blowing installation technology; the second is to open on cement roads Slot, place the micro-optical cable in the trough; the third is to use non-communication dedicated pipes to install the optical cable.

Optical cable for air blowing installation

The air blowing installation method is to use the high-speed air flow of compressed air to blow the micro cable into the designated pipe. The air blowing method has many advantages. Under the high-speed airflow, the micro-cable is suspended in the pipeline, so the change of the terrain and the bending of the pipeline have little effect on the optical cable; the sub-pipe and the micro-cable can be used to increase the fiber assembly density and save the pipeline resources; only need to be deployed in the initial stage The capacity of the optical cable will be expanded in phases according to the development needs, and the optical cable will be blown into the sub-tubes of the built mother tube in batches, saving the initial delivery and avoiding a large number of optical fibers to be idle; the optical fiber branch can be added at any time according to business needs, and the Y-type connection The connector reduces the connector of the optical cable.

The optical cable for air blowing installation is specially designed for laying in the sub-pipe system and micro-pipe. There are mainly sealed micro optical cables and indoor and outdoor non-metallic dual-purpose micro optical cables.

Sealed micro optical cable

It uses a loose fiber optic tube stainless steel tube structure, in addition to the general characteristics of a small optical cable with a small outer diameter and light weight, it also has excellent high and low temperature performance and lateral pressure resistance. The stainless steel tube is made by welding the stainless steel band with a laser. It seals the optical fiber and fiber paste inside. The accurate excess length control technology can ensure the use of the optical cable in complex environments. And stainless steel tube has excellent moisture resistance, physical anti-rodent, anti-ant and anti-acid performance, can give the best protection of optical fiber, minimize the damage of the optical cable, the air-sealed miniature optical cable installation is shown in Figure 1 .

Indoor and outdoor non-metallic dual-purpose optical cable

The location of fiber optic cable connection terminals and maintenance and inspection are mostly located in streets, residential areas, buildings, or communication equipment center computer rooms. These places have fire safety problems and must meet special needs: optical cable products are self-extinguishing and smoke-free. Therefore, most indoor and outdoor non-metallic optical cables use low-smoke halogen-free jacket materials.

Road micro-groove cable

Pavement micro-groove optical cable and air-blown optical cable have similar structures, and are also optical cables with small cable diameter and light weight, low cost, easy to lay, flexible, simple and efficient laying method.

A kind of pavement micro-groove optical cable based on loose stainless steel technology developed in China. The number of optical fiber cores can reach 48, the outer diameter is less than 6.0 mm, and the cable weight is less than 60 kg / km. Among them, the stainless steel tube is not only a loose protective tube of the optical fiber, which can provide the appropriate excess length of the optical fiber, but also a fiber optic cable sealing sleeve, which is used to completely isolate the external moisture from entering the casing, and is also a reinforcing member of the optical cable. Ensure the tensile performance and flattening performance of the optical cable. The stainless steel tube is filled with a thixotropic water-blocking compound to ensure that the optical cable meets the requirements for water permeability, and the steel tube is extruded polyethylene sheath.

Pavement micro-groove fiber optic cable laying only needs to open a narrow groove on the road surface, lay a layer of fine sand on the bottom, lay a buffer layer of foam rods and other materials on the fine sand, then bury the optical cable in the groove, and then on the optical cable Put another layer of buffer layer, and finally fill in cement or bitumen according to the conditions of the road surface to restore the original road surface. When passing through a garden or lawn, first groove the garden or lawn, then lay the optical cable covered with PVC pipes on it, and then backfill to restore the surface. The pavement micro-groove optical cable solves the construction and deployment problems of FTTH when passing through indoor and outdoor concrete floors, garden lawns and other terrains.