As a light transmission tool, optical fiber has been widely used in engineering projects because of its faster transmission rate, more stable signal, higher safety factor, and more environmental protection. The optical fiber cable is a communication cable assembly that uses one or more optical fibers placed in a sheath as a transmission medium and can be used individually or in groups. How much do you know about [fiber knowledge] about optical fiber and optical cable in daily projects?
1. Briefly describe the composition of the optical fiber?
Answer: The optical fiber consists of two basic parts: the core, the cladding, and the coating layer made of transparent optical materials.
2. What are the basic parameters to describe the transmission characteristics of optical fiber lines?
Answer: Including loss, dispersion, bandwidth, cut-off wavelength, mode field diameter, etc.
3. What are the reasons for fiber attenuation?
Answer: Fiber attenuation refers to the reduction of optical power between two cross-sections of an optical fiber, which is related to wavelength. The main causes of attenuation are scattering, absorption, and optical loss due to connectors and splices.
4. How is the fiber attenuation coefficient defined?
Answer: It is defined by the attenuation (dB/km) per unit length of a uniform fiber in a steady state.
5. What is insertion loss?
Answer: It refers to the attenuation caused by inserting optical components (such as insertion connectors or couplers) in optical transmission lines.
6. What is the bandwidth of the optical fiber related to?
Answer: The bandwidth of the optical fiber refers to the modulation frequency when the amplitude of the optical power is 50% or 3dB lower than the amplitude of the zero frequency in the transfer function of the optical fiber. The bandwidth of an optical fiber is approximately inversely proportional to its length, and the product of the bandwidth length is a constant.
7. How many types of optical fiber dispersion are there? What is it related to?
Answer: Optical fiber dispersion refers to the broadening of group delay in an optical fiber, including mode dispersion, material dispersion and structural dispersion. It depends on the characteristics of both the light source and the optical fiber.
8. How to describe the dispersion characteristics of the signal propagating in the optical fiber?
Answer: It can be described by three physical quantities: pulse broadening, optical fiber bandwidth, and optical fiber dispersion coefficient.
9. What is the cut-off wavelength?
Answer: It refers to the shortest wavelength that can only conduct the fundamental mode in the fiber. For single-mode fiber, its cutoff wavelength must be shorter than the wavelength of the transmitted light.
10. What impact will the dispersion of the optical fiber have on the performance of the optical fiber communication system?
Answer: The dispersion of the optical fiber will cause the optical pulse to broaden during transmission in the optical fiber. It affects the size of the bit error rate, the length of the transmission distance, and the size of the system rate.
The phenomenon of broadening of optical pulses in optical fibers caused by different group velocities of different wavelengths in the spectral composition of the light source.
11. What are the most common optical cable structures?
Answer: There are two types: layer twisted and skeleton.
12. What is the main composition of the optical cable?
Answer: It is composed of fiber core, optical fiber ointment, sheath material, PBT (polybutylene terephthalate) and other materials.
13. What does the armor of an optical cable mean?
Answer: It refers to the protective element (usually steel wire or steel belt) used in a special-purpose optical cable (such as a submarine optical cable, etc.). The armor is attached to the inner sheath of the cable.
14. What material is used for the cable sheath?
Answer: The 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.
15. List special optical cables used in power systems.
Answer: There are mainly three kinds of special optical cables: ground wire composite optical cable (OPGW), the optical fiber is placed in the power line of the steel-clad aluminum strand structure. The application of OPGW optical cable plays the dual functions of ground wire and communication, effectively improving the utilization rate of power poles and towers. Wrapped fiber optic cable (GWWOP), where the power transmission line already exists, this kind of fiber optic cable is wound or suspended on the ground wire. The self-supporting optical cable (ADSS) has a strong tensile capacity and can be directly hung between two power poles and towers, and its maximum span can reach 1000m. 16. There are several application structures of
OPGW optical cable? Answer: Mainly include: 1) structure of plastic tube layer twisted + aluminum tube; 2) structure of central plastic tube + aluminum tube; 3) aluminum skeleton structure; 4) spiral aluminum tube Structure; 5) single-layer stainless steel tube structure (central stainless steel tube structure, stainless steel tube layer stranded structure); 6) composite stainless steel tube structure (central stainless steel tube structure, stainless steel tube layer stranded structure). 17. What is the main composition of the stranded wire outside the OPGW optical cable core? Answer: It is composed of AA wire (aluminum alloy wire) and AS wire (aluminum-clad steel wire). 18.
To choose the OPGW optical cable model, what technical conditions should be met?
Answer: 1) The nominal tensile strength (RTS) (kN) of the OPGW optical cable; 2) The number of fiber cores (SM) of the OPGW optical cable; 3) The short-circuit current ( kA); 4) Short circuit time (s); 5) Temperature range (℃).
19. How is the bending degree of the optical cable limited?
Answer: The bending radius of the optical cable should not be less than 20 times the outer diameter of the optical cable, and not less than 30 times the outer diameter of the optical cable during construction (non-stationary state).
Paying attention to Huaguang Yu can bring you more knowledge about optical fiber and optical cable.
Huaguang Yuneng Hangalaxy is an optical communication company. Since 2014, it has been focusing on the R&D and production of 4K 8K signal long-distance optical fiber transmission. Professional optical fiber transmission lines have more than 10,000 large-scale engineering cases in the audio and video industry at home and abroad. Excellent quality standards and accumulated efforts to create a brand reputation of reliable optical fiber transmission lines.
