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Optical Loss: Principles and Applications
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
M.M. Rad, Halit Eren, Martin Maier
Single-mode fibers, shown in Figure 53.2a, are used in transmitting broadband signals over large distances. By choosing a very small core diameter, these fibers allow only one mode of propagation through the fiber. Their attenuation is generally very small and their transmission band is large. Owing to material properties, low attenuations (∼0.25 dB/km) can be expected for wavelengths around 1.3–1.6 μm. Additional attenuation arises from splices and fiber bending. The most common type of single-mode fiber has a core diameter of 8–10 μm and is designed for use in the near infrared (1.5 μm). The mode structure depends on the wavelength of the light used, so that this type of fiber actually supports a small number of additional modes at visible wavelengths. Single-mode fiber provides a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. Single-mode fiber has a much smaller core than multimode fiber and virtually eliminates any distortion that could result from overlapping light pulses, thus providing the least signal attenuation and the highest transmission speeds of any fiber cable type. Single-mode fiber is used in many applications where data are sent at multifrequency (wavelength division multiplexing [WDM]), so only one cable is needed (single-mode on one single fiber).
Fibre-Optic Cable Types and Installations
Published in Abdul Al-Azzawi, Photonics, 2017
Outdoor cables (outside cable plant) must withstand a variety of environment and mechanical stresses during and after installation. The cables must perform with minimal losses over a wide range of temperature and humidity changes. The cable must also have waterproof capabilities, have strength to endure the difficult installation conditions, provide protection against ultraviolet radiation, and provide mechanical protection. There are many types and designs, depending on the manufacturer and application. Outdoor fibre cables are divided into the following types: Overhead cables many be strung from telephone poles or along power lines.Direct burial cables are placed directly in a trench dug in the ground and then covered by soil.Indirect burial cables are placed inside a duct or conduit system.Submarine cables are laid underwater.
Fibre-Optic Cable Types and Installations
Published in Abdul Al-Azzawi, Fibre Optics, 2017
Outdoor cables (outside cable plant) must withstand a variety of environment and mechanical stresses during and after installation. The cables must perform with minimal losses over a wide range of temperature and humidity changes. The cable must also have waterproof capabilities, have strength to endure the difficult installation conditions, provide protection against ultraviolet radiation, and provide mechanical protection. There are many types and designs, depending on the manufacturer and application. Outdoor fibre cables are divided into the following types: Overhead cables many be strung from telephone poles or along power lines.Direct burial cables are placed directly in a trench dug in the ground and then covered by soil.Indirect burial cables are placed inside a duct or conduit system.Submarine cables are laid underwater.
Evaluation of electromagnetic intrusion in brushless DC motor drive for electric vehicle applications with manifestation of mitigating the electromagnetic interference
Published in International Journal of Ambient Energy, 2020
M. Karthik, S. Usha, K. Venkateswaran, Hitesh Panchal, M. Suresh, V. Priya, K. K. Hinduja
Cables are important and the longest part of the system which acts as efficient antennas that pick up or radiates noise. Cables are not the direct source of EMI. To avoid interference through cables shielding is necessary. Shielding surrounds the current-carrying conductor of the cable to protect it from signal interference. Type of Shielding can be selected by considering the following factors: Types of signalNoise levelSystem configuration cost.