A Best Fiber Optical Cable Manufacturer in China since 2000

Properties of an optical fiber

optical fiber is a key component in a fiber optical cable, and fiber attenuation is a most important factor;

The main factors that cause fiber attenuation include: intrinsic, bending, squeezing, Impurities, unevenness, and Fiber splicing.

Intrinsic: refers to the inherent loss of optical fibers, including Rayleigh scattering, inherent，Absorption, etc; Bending: When the fiber is bent, some of the light inside the fiber will be lost due to scattering; Loss caused by falling; Squeezing: Damage caused by slight bending of optical fibers when squeezed; Impurity: The light absorbed and scattered by impurities in a fiber that propagates in the fiber; Uneven: The loss caused by the uneven refractive index of optical fiber materials; Fiber splicing ,The loss generated during fiber optic splicing; This puts forward high requirements for the manufacturing processes of various optical fiber manufacturers, such as how to control the attenuation of optical fibers well.

Some guiding lines help you to choose a right type fiber optic cable for your project.

The selection of optical cables should not only be based on the number of fiber cores and fiber types, but also on Choose the outer sheath of the optical cable based on its usage environment.

1.When directly burying outdoor optical cables, armored optical cables should be selected. When overhead, optional An optical cable with a black plastic outer sheath with two or more reinforcing ribs.

2. When selecting optical cables used in buildings, attention should be paid to their flame retardancy, toxicity, and smoke characteristics. Generally, flame-retardant but smoky types can be selected in pipelines or forced ventilation areas Flame retardant, non-toxic, and smokeless types should be selected in exposed environments.

3. When vertically laying cables inside the building, layer twisted optical cables can be selected; When wiring horizontally, it is possible to choose branching optical cables.

4. If the transmission distance is within 2km, multimode optical cables can be selected, and if it exceeds 2km, please Select single mode optical cable.

Please consult it with our expert engineer to choose a proper type fiber optic cable for your project at a lowest cost.

Types of fiber optical cable connection

Permanent fiber optic connection is also known as hot melt:

This connection is achieved by using a discharge method to connect the connecting points of a fiber optic cable melt and connect together. Generally used for long-distance connection, permanent or semi

-permanent fixed connection. Its main feature is connection attenuation in all connections

The lowest among the connection methods, with a typical value of 0.01-003dB/point. But connecting

Special equipment (welding machine) and professional personnel are required for operation,

And the connection point also needs to be protected by a hot shrinking tube.

Emergency connection , is also known as cold melting:

The emergency connection mainly uses mechanical and chemical methods to connect two

The optical fibers are fixed and bonded together. The main feature of this method is that it connects

The connection is fast and reliable, with a typical attenuation of 0103dB/point. But even

Long term use of contacts can cause instability and significant increase in attenuation

It can only be urgently needed in a short period of time.

Active Connection:

Active connection is a method of connecting stations to stations or stations to optical cables using various fiber optic connection devices (plugs and sockets). This method is flexible, simple, convenient, and reliable, and is commonly used in computer network wiring within buildings. Its typical attenuation is 0.5dB/joint.

Testing for a fiber optic cable

Use Optical power meter or optical time domain reflection plotter (OTDR) to quantitatively measure the optical fiber, which can measure the attenuation of the optical fiber and the attenuation of the connector, and even the position of the optical fiber breakpoint. This measurement can be used to quantitatively analyze the cause of the optical fiber network failure and evaluate the optical fiber network products.

Installation Guide for Fiber Optical Cable

The main methods of laying Fiber optical cables include pipeline laying, direct burial laying, overhead laying, and underwater laying.

1.Before laying the optical fiber cable, the model, specification, and material of the cable should be checked to ensure that they meet the requirements of the design documents and have quality certification documents.

2.Before laying the optical fiber cable, visual inspection and fiber optic disc testing should be carried out. The surface of the insulation layer should be flat, uniform in color, and undamaged. The A/B (head and tail) ends should be well sealed. The optical fiber bundle is composed of different colored optical fibers, and the colored yarn with full color identification should be spiral wound outside. The color code (or full color code) should be clear and complete.

3.When laying optical fiber cables on the ground, they should be laid in designated cable tray areas or independent protective pipes according to the design documents; When laying optical cables underground, the protective tube (bundle) and cable well should be cleaned to ensure cleanliness and smoothness; When laying optical cables in the control room, they should be laid in independent cable trays.

4. When laying optical fiber cables, they should be kept in their natural state and should not be forcefully pulled or bent sharply. When laying optical cables, the bending radius of the cable should not be less than 20 times the outer diameter of the cable. When threading the protective tube, steel wire should be used for guidance and talcum powder should be applied.

5. When laying optical fiber cables, appropriate lengths should be reserved at the turns of the line, in the cable well, and at the terminals, and markings should be made according to the design documents.

6. There should be no joints in the middle of the fiber optic line. The connection of various optical fiber cables should use a universal optical cable box.

When it is inevitable to have intermediate joints, they must be laid along the determined routing sequence according to the number, and ensure that the B end of the front optical cable is connected to the A end of the rear optical cable, so as to ensure that welding can be carried out at the disconnection point during connection and minimize the welding loss value.

7. When laying fiber optical cables, the measures taken for signal attenuation include:

7.1 Plan the direction of cable laying to minimize distance, branching, and cable joints, and ensure tight connections;

7.2 It is best to use a single bus method, connected by a unified communication trunk through a branching device, and not laid in a radial star shape;

7.3 The number and distance of branch points on both sides of the main control station (for systems with a main control station) should be as consistent as possible, which can better ensure the matching of network impedance;

7.4 The branching device should be as close as possible to the control station or operation station;

7.5 Both ends of the network should be connected to a 75 Ω terminal resistor or terminator;

7.6 The distance between fiber optical cables and high-voltage cables should be at least 40cm/kV, and if necessary, they should be vertically crossed;

7.7 Avoid parallel laying with power lines and try to avoid large inductive electrical equipment;

7.8 Avoid areas prone to high temperatures and chemical pollution without damaging the shielding layer of the cable.

8. Requirements for fiber optic fusion and termination for fiber optic cable

8.1 The principle that optical fiber splicing should follow is: when the number of cores is equal, it should be connected to the corresponding colored optical fibers in the bundle tube. When the number of cores is different, the larger number of cores should be connected first, and then the smaller number of cores should be connected in sequence.

8.2 There are three methods for fiber optic connection: fusion, flexible connection, and mechanical connection. But in engineering, fusion welding is mostly used. The use of this fusion method results in low contact loss, high reflection loss, and high reliability.

Before fiber optic fusion, it is necessary to first prepare necessary operating equipment, tools, and materials such as fiber stripping pliers, cutting knives, fusion splicers, heat shrink sleeves, alcohol cotton, etc. to check whether the power supply of the fusion splicer is sufficient and whether all materials are complete. Then, remove the length of the optical fiber outer sheath, steel wire, and other optical fibers to be fusion spliced, and find the corresponding optical fibers that need to be fusion spliced. After making sufficient preparations in the early stage, prepare the end face according to the requirements The four steps of fiber fusion, fiber sorting, and quality inspection are carried out one by one.

8.3 It is strictly prohibited to operate optical fiber fusion in a dusty and humid environment in the open air. The connecting parts, tools, and materials of the optical fiber should be kept clean, and the optical fiber joints should not be affected by moisture. The optical fiber to be cut must be clean and free of dirt. After cutting, the optical fiber should not be exposed to the air for too long, especially in dusty and humid environments.

9. Operation process of fiber optic fusion and fiber optic cable termination

9.1 The steps of fiber optic fusion include: fiber optic stripping, bare fiber cleaning, bare fiber cutting, fiber optic fusion,Fiber sorting and fiber testing.

9.2 Before fiber fusion, the fiber should be tested and comply with the provisions of the product technical documents;

9.3 Fiber optic fusion should be carried out in the order of fiber optic arrangement one by one and marked accordingly; When welding, the operation should be carried out according to the process methods specified in the product technical documents, and special equipment should be used for welding;

9.4 The optical fiber shall not be damaged or broken during the fiber fusion operation; The entire optical fiber fusion process should be completed continuously;

9.5 After fiber fusion, the fiber should be tested and comply with the provisions of the product technical documents; At the same time, keep records.

10. Precautions

10.1 The core of optical fiber is made of quartz glass, which is very easy to break. Therefore, it is never allowed to exceed the minimum bending radius during construction bending.

10.2 The tensile strength of optical fiber is smaller than that of copper wire. Therefore, when manipulating optical cables, it is not allowed to exceed the tensile strength of various types of optical cables. If the bending radius and tensile strength regulations are violated during the laying of the optical cable, it will cause the quartz glass in the fiber core of the optical cable to break, making the cable unusable.

10.3 In order to meet the bending radius and tensile strength, the optical cable is usually wound on a reel during construction. In order to rotate the reel and pull out the optical cable, the reel can be installed on a dedicated bracket. The bending radius of the optical cable should be at least 15 times the outer diameter of the cable (referring to static bending, dynamic bending requires no less than 30 times).

10.4 Based on the situation of the optical cables transported to the construction site and in combination with the actual engineering situation, a reasonable combination of cable trays and cable laying sequence should be made, and the cable tray length should be fully utilized. During construction, it is advisable to lay the entire tray to reduce intermediate joints, and the optical cables should not be arbitrarily cut. The joint position of directly buried optical cables should be arranged in flat terrain and stable foundation areas.