How to connect the fiber optics Cable

In fiber optic cable installations, how the cable is connected to the system is critical to the success of the network. If done correctly, the optical signal will traverse the link with low attenuation and small return loss. Fiber optic cables provide an optimal way to connect fiber optics, which are used in 99% of single-mode applications. This article contains some basics about fiber optic cables, including fiber classification, splicing methods, and more.

Optical cable type

Optical fibers can be divided into single-mode and multi-mode according to the transmission mode.

single mode fiber

A single-mode fiber transmits only one mode of light. Generally speaking, the transmission categories are G.652, G.653, G.654, G.655 and so on. Single-mode fiber can transmit hundreds of megabytes of signals over distances of up to tens of kilometers. Single-mode fiber transmits only the main mode, which means that light travels only along the core of the fiber. The transmission frequency band of single-mode fiber is very wide, so it is suitable for large-capacity, long-distance fiber communication, so single-mode fiber adopts the optical wavelength of 1310nm or 1550nm.

Multimode fiber

 Multimode fibers can transmit multiple modes of optical signals. is G.651. According to the optical mode, it is divided into OM1, OM2, OM3. The maximum transmission distance of 100M signal transmission by multimode fiber is 2 kilometers. Multimode fibers have multiple transmission modes at specific operating wavelengths. Due to dispersion or aberrations, such fibers have poor transmission performance. Equivalent to single mode, the frequency band is relatively narrow, the transmission capacity is relatively small, and the transmission distance is relatively short.

Optical cable laying requirements: 

The bending radius of the optical fiber should be at least 15 times the outer diameter of the optical fiber, and the bending radius of the optical fiber during construction should be at least 20 times the outer diameter of the optical fiber; when laying the optical cable, the rotation speed of the optical cable reel should be synchronized with the laying speed , the indexing speed of the optical cable is generally 900 m/h; when laying the optical cable, there should be a slack arc at the exit of the optical cable, and a buffer margin should be reserved, but the arc should not be too large to avoid the cable kickback; reserved at both ends of the exit The length of the optical cable is 5-10 meters; when laying the optical cable, a label should be made and the laying record should be filled; note that all optical cables should not be exposed.

How to determine the fiber core?

The number of fiber optic cables is the number of glass fibers contained in each fiber optic cable. The following small series will introduce some methods to determine the number of fiber cores.

First, clearly know the number of cabling points on the layer, count the number of switches, and whether the connections between switches are stacked. If stacking, the key is dual-machine hot standby redundancy, and 6 cores are enough.

If you do not need to stack 4-core switches, multiply the number of switches by 4 plus 4 cores for redundancy.

Experience: each layer of wiring cabinets (horizontal wiring cabinets) must erect one optical fiber, generally six cores: use two cores, two cores for backup, two cores for redundancy; some use eight-core optical fibers. The standard minimum configuration is 2 cores per 48 points. Of course, you can choose 4 cores for 48 points, because 2 cores are the smallest unit of optical fiber, and it is more appropriate to leave 2 cores as spares.In addition to the number of optical fiber cores and the type of optical fiber, the selection of the optical fiber cable should also select the outer sheath of the optical fiber according to the purpose of the optical fiber. When choosing, pay attention to the following points:

1. When the outdoor optical cable is directly buried, it is best to choose an armored optical cable. When broadcasting, you can choose a black PE outer sheathed optical cable with two or more reinforcing ribs.

2. When selecting optical cables for construction, attention should be paid to their flame retardant, toxic and fuming characteristics. General ventilation ducts can use flame retardants. Flame retardants should be used in exposed environments.

3. If the wiring is vertical in the building, multi-strand optical cables can be used; if it is horizontal wiring, branch optical cables can be used.

4. Multi-mode optical cable can be used for transmission distance within 2km; relay or single-mode optical cable can be used for more than 2km.

The above are just a few issues to be considered in the splicing process. Actally, flexibility is required. In fact, the wiring environment is complex and diverse, and various problems may arise at any time. This requires us to strictly follow the wiring standards during planning and construction. When we encounter problems, we can face them flexibly and we will solve them successfully.