Fiber optic cabling types and features

Types and characteristics of optical fiber cabling. Optical cables are divided into indoor optical cables, outdoor optical cables, branch optical cables, and distribution optical cables according to different usage occasions.

Optical fibers can be divided into single-mode and multi-mode according to the transmission mode, so monitoring generally uses single-mode optical fibers. Single-mode optical fiber: An optical fiber that only transmits one mode of optical signal. Conventionally, there are transmission grades such as G.652, G.653, G.654, and G.655. Single-mode optical fiber can transmit 100M signals over tens of kilometers. Multi-mode optical fiber: An optical fiber that can transmit multiple modes of optical signals. It is of G.651 grade. It is divided into OM1, OM2, and OM3 according to the optical mode. The longest transmission distance of 100M signals transmitted by multi-mode optical fiber is 2 kilometers.

Optical fiber laying method:

Conventional outdoor optical cables use loose tubes as core containers, which is the most common way of laying optical fiber cores.

Indoor optical cables are usually laid in a tight sleeve.

The core of the large-core optical cable is also combined in a ribbon form to lay the fiber core.

Optical cable structure:

1. The most common optical cable structure is the layer-twisted optical cable, which is generally the structure of optical cables with more than 12 cores. The cavity of the optical cable can accommodate multiple loose tubes. With loose tubes as the basic unit, each loose tube can accommodate 6 -12-core fiber core; the layer-stranded optical cable is the central strength member, and the loose tube is wrapped around the central strength core

For practical application, the fiber core needs to be covered with different colors, a total of 12 colors, and the number of loose tubes of the layer-stranded optical cable is generally within 12, so the number of cores of the layer-stranded optical cable generally ranges from 12 cores to 144 cores. core.

2. The structure of outdoor optical cables below 12 cores is generally a central bundle tube type. This type of optical cable contains a central loose tube inside.

The inner can contain 1-12 cores, and the outer sheath contains two parallel steel wires. The structure diagram is as follows:

3. Ribbon optical cable, also called skeleton groove structure, is generally used as an optical cable structure with a large number of cores. The structure diagram is as follows:

Optical Fiber Supporting Equipment

Optical fiber distribution frame (box): The optical fiber terminal box is to protect the optical fiber and pigtail, and the pigtail is to connect the optical fiber transceiver, optical fiber switch or optical transceiver.

Optical fiber terminal box (splicing box or splicing tray): The optical fiber splicing box is used to fuse two optical fibers together.

Pigtail: One end of the optical fiber pigtail is fused with the optical fiber, and the other end is connected to equipment such as optical fiber transceivers or optical fiber switches.

ODF optical fiber distribution frame and optical coupler: In some large and medium-sized monitoring projects, ODF optical fiber distribution frame and optical coupler may be used. ODF optical fiber distribution frame is mainly used in computer rooms, which can make many optical fibers more regular , easy maintenance.

Optical fiber transceiver: also known as a photoelectric converter, a device that converts optical ports and electrical ports, used in pairs, the electrical port is connected to the switch, and the optical port is connected to the optical fiber pigtail.

Optical fiber module: The optical fiber module is mainly used in optical fiber switches. The optical fiber pigtails can be directly connected to the switch through the optical fiber module, eliminating the need for optical fiber transceivers, but the price of optical fiber switches is relatively high.

Pigtail interface type

The commonly used interface types of pigtails are FC, ST, FC/APC, SC/APC, SC, etc. The commonly used interface on fiber optic transceivers is SC interface, so when selecting pigtails, it is first necessary to determine the fiber optic transceiver or fiber optic switch used interface type, otherwise it cannot be inserted.