Understanding Fiber Opitc Cable, Single Mode, Multi ModePosted by Bella Tse on November 28th, 2019 Basic structure of optical fiber Both the core and cladding are made of glass of different refractive indices. The innermost part is the core, and the second layer on the top of the core is the cladding of an optical fiber. They have different refractive indices, and the refractive index of the core is always greater than the index of the cladding. This index difference causes total internal reflection to occur at the index boundary along the length of the fiber. A light ray is injected into the fiber optic cable, total internal reflection takes place so that it can transmit down the fiber and does not escape through the sidewalls. The jacket protects the fiber from damage and moisture. It is made up of flexible and abrasion resistant varieties of plastic to increase the flexibility of the fiber. As we knew, the core and cladding are made of glass and cannot be bent and fragile. Usually, the jacket has another layer beneath it called buffer. The buffer and the jacket together protect the cable from environmental hazards. Some of the optical fiber also has an outer jacket for further protection. The color of this outer layer of fiber is standardized so you can tell what type of fiber you have. Normally, there are two types of optical fiber: single mode and multi mode. Single-mode fiber is a single glass fiber strand used to transmit a single mode or ray of light. Single mode fiber with a relatively narrow diameter, through which all signals travel straight down the middle without bouncing off the edges. Single-mode fiber features only one transmission mode. But Multimode fiber can carry multiple light rays (modes) at the same time because of its bigger diameter. Transmission characteristics of optical fiber Fiber dispersion includes Material dispersion, Waveguide dispersion and Modal dispersion. The material dispersion and waveguide dispersion are usually caused by different signal frequencies. And the modal dispersion is caused by the signal’s multimode. Signals that are not in a single mode can cause modal dispersion. Single-mode fiber is so small in diameter that rays of light can reflect internally through one layer only. So there is only material dispersion and waveguide dispersion, and there is no modal dispersion. However, multimode fibers have modal dispersion. The dispersion of the fiber not only affects the transmission capacity of the fiber, but also limits the relay distance of the fiber-optic communication system. Compared with multimode fiber, single-mode fiber has higher bandwidth and can carry signals for longer distances. Single mode optical fiber Multi mode optical fiber Both single mode fiber and multimode fiber have a cladding diameter of 125μm. Single mode fiber or multi mode fiber? Multimode fiber has a large diameter core, which can transmit a variety of modes of light. In multimode, since the fiber core size is large, the signal “disperses” quickly, and the inter-modal dispersion is larger. Because the light travels different paths, the longer the cable is, the more distortion is caused by the different paths arriving at the receiving end at slightly different times. This is why single mode cable works better for longer distances. Multimode optical fiber is commonly used short distances, audio/video applications, and Local Area Networks (LANs). And OM3/OM4/OM5 multimode fibers can support high rate data transmission.
Cost Which mode of fiber to choose depends more on the application environment you need. HYC can provide various types of fiber patch cords. HYC Co., Ltd(HYC)is a national Hi-tech optoelectronics company engaged in R&D, manufacture, and marketing of fiber optical products. Providing professional products and services for fiber connectivity, WDM, PLC splitter, and high-density datacom cabling. HYC products and solutions widely applied in 4G/5G, Data Center and Cloud Computing industry, etc. Like it? Share it!More by this author |