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1. Optical fiber scattering loss The scattering inside the fiber will reduce the transmitted power and cause loss. The most important of scattering is Rayleigh scattering, which is caused by changes in density and composition inside the fiber material.

1. Classification of fiber loss Optical fiber loss can be roughly divided into the inherent loss of the optical fiber and the additional loss caused by the operating conditions after the optical fiber is made. The specific breakdown is as follows:

1. What is the nonlinearity of fiber? Answer: It means that when the optical power of the incoming fiber exceeds a certain value, the refractive index of the optical fiber will be nonlinearly related to the optical power, and Raman scattering and Brillouin scattering will occur, which will change the frequency of the incident light.

1. What are the two commonly used single longitudinal mode semiconductor lasers? Answer: DFB lasers and DBR lasers are both distributed feedback lasers, and their optical feedback is provided by distributed feedback Bragg gratings in the optical cavity.

1. How many types of fiber optic connectors are commonly used? Answer: According to different classification methods, fiber optic connectors can be divided into different types. According to different transmission media, they can be divided into single-mode fiber optic connectors and multi-mode fiber optic connectors; according to different structures, they 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 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.

1. 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.

1. What is the significance of the numerical aperture (NA) of a step index fiber? Answer: Numerical Aperture (NA) indicates the light-receiving ability of the fiber. The larger the NA, the stronger the light-collecting ability of the fiber.

What is "counting the east and counting the west"? The National Development and Reform Commission and other departments have jointly issued a document recently, agreeing to start the construction of national computing power hub nodes in Beijing-Tianjin-Hebei, Yangtze River Delta, Guangdong-Hong Kong-Macao Greater Bay Area, Chengdu-Chongqing, Inner Mongolia, Guizhou, Gansu, and Ningxia, and planned 10 countries. data center cluster. So far, the overall layout design of the national integrated big data center system has been completed, and the "East and West" project has been officially launched.

1. What does "1310nm" or "1550nm" in common optical test instruments refer to? Answer: It refers to the wavelength of the optical signal. The wavelength range used in optical fiber communication is in the near-infrared region, and the wavelength is between 800nm ​​and 1700nm. It is often divided into short wavelength band and long wavelength band, the former refers to 850nm wavelength, and the latter refers to 1310nm and 1550nm.

1. What is the test principle of Optical Time Domain Reflectometer (OTDR)? What is the function? Answer: OTDR is made based on the principle of light backscattering and Fresnel reflection. It uses the backscattered light generated when light propagates in the fiber to obtain attenuation information, which can be used to measure fiber attenuation, splice loss, fiber fault location, and Knowing the loss distribution of optical fibers along the length is an essential tool in the construction, maintenance and monitoring of optical cables. Its main index parameters include: dynamic range, sensitivity, resolution, measurement time and dead zone.

1. What are the dispersions of optical fibers? What is it about? 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.

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

With the development of the communication industry, optical communication products to meet various needs have been put into the market. We may know little about the classification of this type of products and their characteristics. So, in today's article, let's take a brief look at one type of product: fiber optic connectors.

Single mode: 8/125μm, 9/125μm, 10/125μm Multimode: 50/125μm European standard; 62.5/125μm American standard

In the current general optical fiber cabling network, because the technology and quality of the optical fibers used in the wiring are generally stable, the characteristics of the optical fibers composed of optical fibers and various optical fiber connectors, jumpers, pigtails and other components are relatively stable. And in the actual use of wiring, they are relatively fixed, so most of the reasons that may actually affect the stability of the optical fiber network are concentrated in the connection technology of the optical fiber.