Optical fiber is widely used in the field of communication because of its specific performance. Although the construction level of optical fiber cable has been significantly improved with the improvement of construction technology, there are still natural and artificial problems. This paper mainly expounds the common problems and countermeasures of optical cable construction for reference.As an important means of long-distance communication, optical cable communication has the characteristics of large communication capacity, long transmission distance and good transmission quality. Many problems need to be overcome and resolved.1. Common problems in the construction of communication optical cables（1）. Environmental impact. The burial environment of the optical cable is relatively humid, especially in high temperature and high salt areas, which will corrode the external materials of the optical cable to a certain extent, thereby affecting the internal optical fiber structure and causing hydrogen loss; during the construction process, it is often interfered by external forces, causing hydrogen loss. , After the hydrogen loss problem occurs, the optical fiber will have an incremental attenuation between 1310-1550nm. If the attenuation amplitude reaches a certain value, the signal transmission quality does not meet the standard. The only solution is to change the cable, which will affect normal communication. In addition, the optical cable passes through a lot of mountains, forests, and vegetation, and is easily affected by rats and other influences, resulting in increased loss or even fiber breakage.（2）. Continuity loss. During the splicing process of the communication optical cable, the interface will have a large loss due to the following reasons, even exceeding the specified standard range: First, during the cutting process of the optical fiber, the end face of the optical fiber is prone to breakage, fragmentation, irregularity and other phenomena, resulting in excessive splicing loss. ;Secondly, the optical fiber cable splicing operation is generally carried out in the field, and the harsh splicing environment is easy to attract dust on the section or surface of the optical fiber, thereby increasing the optical fiber loss after the connection; the third is that the two sections of the optical cable connected will increase due to the difference in parameter characteristics. loss of the interface.（3）. Connector loss. The splice loss of the optical fiber usually has a specific range, generally 0.08db. If it exceeds the range, the optical cable needs to be repaired or replaced. The reasons that affect the excessive splice loss mainly include the following three aspects: First, because of the optical fiber cutting tool and welding process The problem leads to a large splicing loss; the second is that due to the limitation of the blind zone of the optical time domain reflectometer, it may cause a large loss at the optical fiber connector; the third is that the test results of the optical time domain reflectometer caused by the optical fiber splice loss appear. The illusion causes loss at the joint.（4）. Improper laying. During the construction process, due to the lack of site investigation of the route, the lack of understanding of the topographic and geological conditions, and the lack of careful cleaning of the laying trenches, the staff could easily damage the outer skin of the optical cable during laying, and the geological changes could easily lead to the interruption of the optical cable. A communication accident occurs. In addition, some construction units lack corresponding rules and regulations and quality management systems, and construction personnel lack strong professional skills and sense of responsibility, and pay less attention to laying quality. Affects link signaling.Fiber hope fiber optic cable and patch cord manufacturers can provide high-quality fiber optic cables,fiber pigtails, fiber patch cords, single-mode multi-mode fiber, welcome to inquiry!
1. What are the causes of noise in optical fiber communication systems?There are noise caused by unqualified extinction ratio, noise caused by random variation of light intensity, noise caused by time jitter, point noise and thermal noise at the receiving end, mode noise of optical fiber, noise caused by pulse broadening caused by dispersion, and mode distribution noise of LD. , the noise generated by the frequency chirp of the semiconductor laser and the noise generated by the reflection.2. In the construction of the transmission network, what kind of optical fiber is mainly used? What are its main features?There are mainly three types, namely G.652 conventional single-mode fiber, G.653 dispersion-shifted single-mode fiber, and G.655 non-zero dispersion-shifted fiber.The dispersion of G.652 single-mode fiber in the C-band 1530-1565nm and L-band 1565-1625nm is relatively large, generally 17-22psnm·km, and the system speed is above 2.5Gbit/s, which requires dispersion compensation. At 10Gbit/s, the cost of dispersion compensation is large. It is the most common fiber in transmission networks.The dispersion of G.653 dispersion-shifted fiber in C-band and L-band is generally -1～3.5psnnm·km, zero dispersion at 1550nm, and the system speed reaches 20gbit/s and 40Gbit/s respectively, which is a single-wavelength ultra-long distance transmission Best fiber. However, since DWDM has zero dispersion characteristics, it will produce nonlinear effects during capacity expansion, resulting in signal crosstalk and four-wave mixing FWM, so it is not suitable for DWDM.G.655 non-zero dispersion-shifted fiber: G.655 non-zero dispersion-shifted fiber has a dispersion of 1-6 psnm·km in the C-band and 6-10 psnm·km in the L-band. The dispersion is small, avoiding the zero dispersion region. It can not only suppress FWM, but also can be used for DWDM expansion and high-speed systems. The effective area of the new G.655 fiber can be expanded to 1.5 times the effective area of ordinary fibers. The effective area can reduce the power density and nonlinear effects of the fiber.3. What is fiber nonlinearity?When the input optical power exceeds a certain value, the refractive index of the fiber will have a nonlinear relationship with the optical power, and Raman scattering and Brillouin scattering will occur, which will change the frequency of the incident light.4. What effect does fiber nonlinearity have on transmission?Non-linear effects can cause some additional losses and disturbances that degrade system performance. The optical power of WDM system is large, and the transmission distance along the optical fiber is long, resulting in nonlinear distortion. There are two types of nonlinear distortions: stimulated scattering and nonlinear refraction. Stimulated scattering includes Raman scattering and Brillouin scattering. Both types of scattering reduce the energy of the incident light, causing losses. When the input power is very small, it can be ignored.5. What is passive optical network?Passive Optical Network (PON) refers to an Optical Distribution Network (ODN) between OLT and ONU without any active electronic equipment. It is a point-to-multipoint optical fiber transmission and access technology. The downlink adopts broadcast mode, and the uplink adopts time division multiple access mode, which can flexibly form tree, star, bus and other topological structures, and only need to install a simple optical splitter at the optical branch point, so it has the advantages of saving optical cable resources, It has the advantages of sharing bandwidth resources, saving computer room investment, fast network construction, and low cost of comprehensive network construction. Passive optical networks include ATM-PON and Ethernet-PON.Fiber hope fiber optic cable and patch cord manufacturers can provide high-quality fiber optic cables,fiber pigtails, fiber patch cords, single-mode multi-mode fiber, welcome to inquiry!
1. How to limit the bending of optical cable?The bending radius of the optical cable is not 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-static).2. What should be paid attention to in ADSS optical cable project?The mechanical design of the optical cable, the determination of the lifting point, the selection and installation of the supporting hardware are three key technologies.3. What are the main optical cable accessories?Optical cable hardware refers to the hardware used to install optical cables, mainly including: tension clamps, suspension clamps, shock absorbers, etc.4. Optical fiber connectors have two basic performance parameters. what are they?Optical fiber connectors are commonly known as flexible connectors. Aiming at the optical performance requirements of single-fiber connectors, the two most basic performance parameters, insertion loss and return loss, are studied.5. What are the common fiber optic connectors?According to different classification methods, fiber optic connectors can be divided into different types. According to the different transmission media, it can be divided into single-mode fiber optic connectors and multi-mode fiber optic connectors. According to the different structure, it can be divided into FC, SC, ST, D4, DIN, biconic, mu, LC, MT and other types. According to the pin end face of the connector, it can be divided into FC, PC (UPC) and APC. Commonly used fiber optic connectors: FC/PC fiber optic connectors, SC fiber optic connectors, and LC fiber optic connectors.6. What is the insertion loss (or insertion loss) of a fiber optic connector?Refers to the reduction in the effective power of the transmission line due to the intervention of the connector. For users, the smaller the value, the better. According to ITU-T, this value must not be greater than 0.5dB7. What is the return loss (or reflection attenuation, return loss, return loss) of the fiber optic connector?It is a measure of the input power component reflected back from the connector and back down the input channel. Its typical value should not be less than 25dB.Fiber hope fiber optic cable and patch cord manufacturers can provide high-quality fiber optic cables,fiber pigtails, fiber patch cords, single-mode multi-mode fiber, welcome to inquiry!
1. What is the birefringence of a single-mode fiber?There are two orthogonal polarization modes in a single-mode fiber. When the fiber is not perfectly cylindrically symmetric, the two orthogonal polarization modes do not degenerate. The absolute value of the difference between two orthogonal polarization modes is birefringence.2. What is the most common optical cable structure?There are stranded optical cable, bundled optical cable, skeleton optical cable and ribbon optical cable.3. What are the main components of the optical cable?It is mainly composed of fiber core, fiber paste, sheath material, polybutylene terephthalate and other materials.4. What is the armor of the optical cable?Refers to the protective element (usually steel wire or steel tape) used in special-purpose optical cables (such as submarine cables, etc.), and the armor is attached to the inner sheath of the optical cable.5. What material is used for the cable sheath?Optical cable jackets are usually made of polyethylene (PE) and polyvinyl chloride (PVC) materials, and their role is to protect the cable core from the outside world.6. List the special optical cables used in the power system.Aerial optical cables parallel to power lines are generally referred to as power overhead optical cables. According to the materials used, they can be divided into two categories: metal optical cables and dielectric optical cables. Three additional types. They are optical fiber composite ground wire (OPGW), optical fiber composite phase wire (OPPC), metal self-supporting optical cable (MASS), all-dielectric self-supporting optical cable (ADSS), bundled optical cable (ADL) and winding optical cable (GWWOP). kind.Fiber hope fiber optic cable and patch cord manufacturers can provide high-quality fiber optic cables,fiber pigtails, fiber patch cords, single-mode multi-mode fiber, welcome to inquiry!