Laying fiber optic cables directly into the ground

Using specialized mechanisms, a micro trench is made in the roadbed with a width of up to 15 mm and a depth of 40 to 100 mm, into which a specialized fiber-optic cable is laid. The laid cable is covered with a porous rubber tow, the diameter of the tow is selected so that it fits snugly into the trench and serves as a spacer. After this, the trench is poured with bitumen.

The cable designed for this installation method is a monotube design and consists of one metal module made of a copper alloy, inside of which optical fibers are contained. The interior of the fiber module is filled with a hydrophobic compound. The external diameter of the module is 5 mm. The module contains bundles of optical fibers. For identification, the optical fibers in one bundle have a different color, and each bundle has a winding of colored synthetic filaments. The number of optical fibers in the beam is up to 12 pieces. A cable can contain up to 5 bundles of optical fibers. Thus, the number of optical fibers in the cable can reach sixty. Outside the cable is covered with a protective polyethylene sheath. The outer diameter of the cable is 7 mm, weight - about 110 kg/km.

Fiber optic cable for micro trench installation

This design of the fiber optic cable provides high resistance to temperature fluctuations and mechanical stress. Permissible tensile strength is 1 kN. The permissible bending radius when laying is 70 mm. Operating temperature range - from -40 to + 70 ° С.

It should be noted that, as in the case with other fiber-optic cables, installation work should be carried out at an ambient temperature of at least -5 ° C.

To join the building lengths of the fiber-optic cable, special couplings have been developed, designed to be installed on the soil surface so that the coupling hatch is flush with the road surface. These are couplings of the type through the passage. The round case is made of stainless steel and is designed for splicing up to two cable construction lengths, that is, it has 4 cable entries. There are modifications of couplings for splicing fiber optic cables of various capacities. The clutch case has a round shape, the diameter is calculated in such a way as to enable the calculation of the technological stock of optical fibers inside the clutch case.

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