Fiber optic cable knowledge

1. How is the fiber composed?

A: An optical fiber consists of two basic parts: the core and cladding made of transparent optical material, and the coating.

2. What are the basic parameters of the transmission characteristics of optical fiber lines?

A: Including loss, dispersion, bandwidth, cutoff wavelength, mode field diameter, etc.

3. What is the cause of fiber attenuation?

Answer: The attenuation of a fiber refers to the reduction in optical power between two cross-sections of a fiber, which is related to the wavelength. The main causes of attenuation are scattering, absorption, and optical losses due to connectors and splices.

4. How many kinds of dispersion of optical fiber? What is it related to?

Answer: The dispersion of an optical fiber refers to the expansion of the group delay in a fiber, including modal dispersion, material dispersion and structural dispersion. Depends on the characteristics of both the light source and the fiber.

5. What is the cutoff wavelength?

Answer: It refers to the shortest wavelength that can only transmit the fundamental mode in the fiber. For single-mode fibers, the cutoff wavelength must be shorter than the wavelength of the transmitted light.

6. What are the most common optical cable structures?

Answer: There are two types: layer twist type and skeleton type.

7. What is the main composition of the optical cable?

Answer: It is mainly composed of: fiber core, optical fiber ointment, sheath material, PBT (polybutylene terephthalate) and other materials.

8. What is the armor of the optical cable?

Answer: It refers to the protective element (usually steel wire or steel tape) used in special-purpose optical cables (such as submarine optical cables, etc.). The armor is attached to the inner jacket of the cable.

9. What material is used for the cable sheath?

Answer: The optical cable sheath or sheath is usually composed of polyethylene (PE) and polyvinyl chloride (PVC) materials, and its function is to protect the cable core from external influences.

10. What are the special optical cables used in the power system.

Answer: There are mainly three kinds of special optical cables: ground wire composite optical cable (OPGW), winding optical cable (GWWOP), self-supporting optical cable (ADSS).