Regarding the problem of fiber signal attenuation, it is mainly divided into two aspects: intrinsic attenuation and extrinsic attenuation. The intrinsic attenuation is determined by the material made of the fiber, while the extrinsic attenuation is closely related to the construction process. So in terms of reducing the intrinsic attenuation, we have to learn to choose the appropriate fiber. For example, the high-quality fiber provided by Fast (FS) can minimize signal attenuation. In addition, note that different environments choose different fibers.
There are three types of fiber used in common environments:
1. If the transmission distance is within 2km, multi-mode fiber can be selected, and relay or single-mode fiber can be used for more than 2km.
2, the use of optical fiber in the building should pay attention to its flame retardant, toxic and smoke characteristics. Generally, flame-retardant but smoky types can be selected in pipes or forced ventilation; If it is exposed to the environment, should choose flame retardant, non-toxic and smoke-free type.
3. When outdoor fiber optic cable is buried directly, it is appropriate to choose armored fiber optic cable. For overhead, an optical fiber with a black plastic outer sheath with two or more stiffeners can be selected.
There are several basic requirements for fiber wiring:
1. The detection optical fiber is stored in the cable tray, and the protective packaging is reserved before installation, and the cable tray is kept straight to prevent the collapse of the cable and damage to the detection optical fiber. In the process of storage and transportation, always pay attention to the detection of fiber bending radius and tension limit.
2. In the process of fiber wiring, the tensile force of Φ0.9 fiber is less than 4Kg; Φ3 fiber tension is less than 10Kg; The armored fiber tension is less than 30Kg
3. When laying out the fiber in the field, the thin rod should be used to cross the center of the fiber winding disc horizontally, rotate the winding disc and put out the wire. It is forbidden to put the fiber winding disc on the ground and rotate the fiber from the disc.
4. The end of the fiber away from the temperature measuring host should be processed as follows: take the last 30 cm long Φ0.9 fiber (if there is a sheath or armor, it should be removed), and wrap the fiber around a small circle with a diameter of 1 cm for 10 turns.
5. The bending radius of the detection fiber shall be greater than 30mm, and the detection fiber shall not be seriously worn or crushed when passing through the wall or pipe.
6, multiple fiber through the same longer metal or PVC pipe, to ensure that the fiber through a, can not be divided through the fiber.
7, the detection of optical fiber is prohibited to fall, twist, gravity impact, over-force stretching, etc., to avoid the detection of optical fiber core fracture.
8. The type and specification of optical fiber used in the project shall conform to the design regulations and requirements.
