How to monitor the security engineering fiber?

Optical fiber classification:

The optical fibers are classified into indoor optical fibers, outdoor optical fibers, branch optical fibers, and distribution optical fibers according to different occasions.

According to laying methods: Self-supporting overhead optical fiber, pipeline optical fiber, armored buried optical fiber and submarine optical fiber.

Divided by optical fiber structure: beam tube type fiber, layered stranded optical fiber, skeleton type optical fiber, clasp type optical fiber, ribbon type optical fiber, non-metal optical fiber and branchable optical fiber.

Divided by purpose: optical fiber for long-distance communication, short-distance outdoor optical fiber, mixed optical fiber and in-building optical fiber;

Fibers can be classified into single-mode and multi-mode according to the transmission mode, and monitoring generally uses single-mode fiber.

Single-mode fiber: Optical fiber that only transmits one mode of optical signal, conventional G.652, G.653, G.654, G.655, etc. transmission class classification, single-mode fiber transmission 100M signal distance up to tens of kilometers. The single-mode fiber transmits only the main mode, which means that light is transmitted only along the inner core of the fiber. Since the mode dispersion is completely prevented, the transmission band of the single-mode fiber is very wide, and the weak electric coil is securely protected. Therefore, it is suitable for large-capacity and long-term use. Distance optical fiber communication, single-mode optical fiber used wavelength 1310nm or 1550nm.

Multi-mode optical fiber: Optical fiber that can transmit multiple modes of optical signals, which is G.651 grade. It is divided into OM1, OM2, OM3 according to the optical mode, and the farthest transmission distance of multi-mode optical fiber transmits 100 megabit signals. In a multi-mode optical fiber, multiple modes are transmitted in an optical fiber at a certain operating wavelength. This kind of optical fiber is called a multi-mode optical fiber. Due to dispersion or aberration, the optical fiber has a relatively narrow transmission band and transmission capacity. Smaller, shorter distances.

Fiber laying methods and requirements

Fiber laying method:

The conventional outdoor optical fiber is a container with a loose tube as the core, which is the most common fiber core laying method;

Indoor optical fiber is usually tight-type laying;

The core of a large core count fiber also has a combination of laying the fiber cores in a ribbon-like manner.

Fiber laying requirements:

The bend radius of the fiber should be at least 15 times the outer diameter of the fiber, and should be at least 20 times during the construction process;

When laying out the optical fiber, the rotation of the optical fiber tray should be synchronized with the deployment speed. The index of the optical fiber is generally 15 meters per minute.

When laying out the optical fiber, the optical fiber should be kept at a loose arc at the outlet, and the buffering margin should be kept. It should not be too much to avoid the occurrence of back buckle in the optical fiber.

The length of the fiber reserved at both ends is 5-10 meters;

Labeling should be done when laying fiber, and fill-in records should be filled in;

All fibers should not be exposed.

Optical core selection

The number of fiber cores is the number of glass fibers contained in each fiber.

The following small series gives you some methods to determine the number of fiber cores.

First, the number of routing points in the layer is clearly known, the number of switches is calculated, and whether the connections between the switches are stacked or unstacked. If it is stacked and the core switch is dual-system hot standby redundancy, 6 cores are sufficient (2 cores each with 2 cores and 2 cores redundant).

If you do not stack a switch to 4 cores, the number of switches is multiplied by 4 plus 4 cores of redundancy. (Note: Redundancy: as long as it is more than the use of, redundant is called redundant master and standby: one used, the other is exactly the same as the backup; hot backup: both at work; cold backup: the backup device is in standby mode.)

Experiences and practices: Each floor wiring closet (horizontal wiring cabinet), set up an optical fiber, generally six-core: two-core use, two-core spare, two-core redundancy; also use eight-core optical fiber. Security weak circuit, the standard minimum configuration of 2 cores every 48 points. Of course, 48 points can be selected for 4 cores, because 2 cores are the smallest units of fiber, and it is more appropriate to keep 2 cores as a backup.

The above is a description of how to determine the number of fiber cores. Everyone can find out. Backup can be chosen because of people, so the fiber out of the number of differences in the number of more, according to the selection of the election is only to ensure a minimum selection plus a backup core number on it.

be careful

The selection of optical fiber is based on the number of optical fibers and the type of optical fiber, security weak electric circle, but also according to the use of optical fiber to choose the outer sheath of the optical fiber, in the selection should pay attention to the following points:

1. When using outdoor optical fiber for direct burial, armored optical fiber should be selected. When it is overhead, two or more black plastic outer sheathed optical fibers of reinforcing ribs can be used.

2. The optical fiber used in a building should pay attention to the characteristics of its flame retardant, poison and smoke. Generally, in the pipeline and in the forced ventilation, the type of flame retardant and smoke can be selected. In the exposed environment, flame retardant should be used. , smokeless and non-toxic types.

3. In the vertical wiring in the building, layer twisted optical fiber can be used; in horizontal wiring, branch fiber can be selected.

4. Optional multi-mode optical fiber with a transmission distance of less than 2km; optional relay or single-mode optical fiber over 2km.

The above are just a few of the issues considered from the application side, and they need to be flexibly implemented. In fact, the wiring environment is complex and diverse, and various problems may arise at any time. This requires us to strictly implement the wiring standards in planning and construction. When problems are encountered and the analysis is flexible, it will be resolved satisfactorily.