What Is Single Mode Fiber-Optic Cable?

Single-mode optical cable is a kind of optical fiber transmission equipment.

Single-mode fiber optic cable

Single-mode optical cable is a kind of optical fiber transmission equipment.

Chinese name

Single-mode fiber optic cable

Foreign name

Single mode optical cable

Component

Core, cladding and coating

Function

transmit information

Material

Quartz, glass fiber, etc.

It is mainly composed of fiber core, cladding and coating layer; the core is made of highly transparent material; the refractive index of the cladding is slightly smaller than that of the fiber core, resulting in an optical waveguide effect, and most of the electromagnetic field The binding is transmitted in the core of the fiber; the role of the coating layer is to protect the optical fiber from water vapor and mechanical abrasion, while increasing the flexibility of the optical fiber. Outside the coating, a plastic jacket is often added.

According to the following raw materials of optical fibers, optical fibers can be divided into the following types:

(1) Quartz fiber

(2) Multi-component glass fiber

(3) Plastic-clad fiber

(4) All plastic optical fiber

According to the refractive index distribution on the cross section of the optical fiber, the optical fiber can be classified into a step index type and a graded index type (also referred to as a gradient index type).

For step-index fibers, the refractive index distribution is uniform in the core, and the refractive index changes abruptly at the interface between the core and the cladding. For graded-index fibers, the refractive index changes continuously in the core.

n1> n2 (refractive index of the n1 core n2 of the cladding) is a necessary condition for the fiber to guide the transmission of light waves in the core. For a step index fiber, it can make the light waves cross the core and the cladding. Formed on the interface

Single-mode fiber optic cables can be divided into the following types according to the same raw materials of optical fibers:

(1) Quartz fiber

(2) Multi-component glass fiber

(3) Plastic-clad fiber

(4) All plastic optical fiber

product detailed information

Single-mode fiber optic cable and

First, the main mode of single-mode optical cable connection

1. Fixed connection. It is mainly used for permanent connection between multi-mode and single-mode optical cables in optical cable lines. Most of them use fusion welding, but also use bonding and mechanical connection. The characteristics are that the joint loss is small, the mechanical strength is high, and the equipment needs a welding machine.

2. Active connection. It is mainly used for multi-mode and single-mode fiber optic cables and transmission system equipment, and for connection with instruments. It is mainly connected through optical connection plugs. The characteristic is that the joint is flexible and better, it is convenient to change the connection point, and the loss and reflection are large. The insertion loss is also very good. It can be dozens of RMB. You can buy the finished product directly. If you want to buy parts, you also need end-face polishing and grinding equipment. That is too expensive.

3. Temporary connection. It is generally used to measure the coupling connection between the pigtail and the tested multimode and single-mode optical cable. The characteristics are convenience and flexibility, low cost, and low requirements on loss. This method is often used for temporary measurement. It can also be glued with a fusion splicer or V-groove.

Second, the requirements for single-mode optical cable connection

1. Requirement for fixed connection Fixed connection of optical fiber is a key technology in optical cable line. The requirements for fixed connections are as follows: small connection loss and good consistency; good connection loss stability, and there should be no additional loss in the general temperature difference range; sufficient mechanical strength and service life; operation should be as simple as possible , Easy to operate; joints should be small, easy to place and protect; low cost, easy to process materials.

2. Requirement for active connection For the detachable optical fiber connection method, mechanical connectors are used to achieve it. The requirements are as follows: the connection loss should be small, and the loss of the single-mode optical cable is less than 0.5dB; it should have good repeatability and interchangeability. After repeated plugging and swapping of accessories, there is still better consistency; it has better stability, the insertion loss is stable after the connector is fastened, and it is not affected by temperature changes; it must be small in size and light in weight; yes A certain intensity; affordable.

3. Requirement for temporary connection The temporary connection of the optical fiber can also be spliced with a splicer. The loss is required to be as low as possible. When using a V-groove and a capillary connection, a ratio liquid must be added, otherwise Fresnel reflection cannot be eliminated.