SPLICING OF FIBER CABLE

CONTENTS 1.INTRODUCTION 2.OPTICAL FIBER CABLE 3.CONSTRUCTION 4.PRINCIPLE OF OPERATION 5.MULTIMODE FIBER 6.SINGLE MODE FIBER 7.SPECIAL PURPOSE FIBER 8.SPLICING OF FIBER CABLE 9.OPTICAL FIBER COMMUNICATION 10.FIBER OPTIC SENSOR 11.PROTECTION 12.APPLICATIONS OF OPTICAL FIBER CABLE 13.ADVANTAGE OF FIBER CABLES 14.DISADVANTAGES OF FIBER CABLE

INTRODUCTION An optical fiber is a flexible, transparent fiber made of very pure glass (silica) not much wider than a human hair that acts as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. Fibers are used instead of metal wires because signals travel along them with less loss.

OPTICAL FIBRE CABLE :: Optical fiber is the latest underground cable that is being used extensively in all the networks including long distance trunks, junction circuits and even the local subscriber loops to enhance the data transmission. An optical fiber is a flexible, transparent fiber made of very pure glass (silica).

CONSTRUCTION The construction of an optical fiber cable consists of an inner glass core surrounded by a glass cladding which has a lower refractive index. Digital signals are transmitted in the form of intensity-modulated light signal which is trapped in the glass core.

Principle of operation An optical fiber is a cylindrical dielectric waveguide (nonconducting waveguide) that transmits light along its axis, by the process of total internal reflection. The fiber consists of a core surrounded by a cladding layer, both of which are made of dielectric materials. To confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. The boundary between the core and cladding may either be abrupt, in step-index fiber, or gradual, in graded-index fiber.

MULTIMODE FIBER Fiber with large core diameter (greater than 10 micrometers) may be analyzed by geometrical optics. Such fiber is called multi-mode fiber, from the electromagnetic analysis

SINGLE MODE FIBER The structure of a typical single-mode fiber. 1. Core: 8 µm diameter 2. Cladding: 125 µm dia. 3. Buffer: 250 µm dia. 4. Jacket: 400 µm dia. Fiber supporting only one mode is called single-mode or mono-mode fiber.

SPECIAL PURPOSE FIBER Some special-purpose optical fiber is constructed with a non-cylindrical core and/or cladding layer, usually with an elliptical or rectangular cross-section. Such fiber uses diffraction effects instead of or in addition to total internal reflection, to confine light to the fiber's core

SPLICING OF OPTICAL FIBER Optical fibers may be connected to each other by connectors or by splicing, that is, joining two fibers together to form a continuous optical waveguide. The generally accepted splicing method is arc fusion splicing, which melts the fiber ends together with an electric arc. For quicker fastening jobs, a "mechanical splice" is used. Fusion splicing is done with a specialized instrument

METHOD OF SPLICING Fusion Splicing- Fusion splicing is done with a specialized instrument. 2. Mechanical Splicing – For more fastening mechanical splicing is used.

Optical Fiber Communication Optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables. A single fiber can carry much more data than electrical cables such as standard category 5 Ethernet cabling, which typically runs at 1 Gbit/s .

Fiber Optic Sensors Fibers have many uses in remote sensing. In some applications, the sensor is itself an optical fiber. In other cases, fiber is used to connect a non-fiberoptic sensor to a measurement system. Depending on the application, fiber may be used because of its small size, Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the property to measure modulates the intensity, phase, polarization, wavelength, or transit time of light in the fiber.

PROTECTION Fiber cables require Protection:- 1.from probable mechanical damages. 2. from water and chemicals or soil conditions. 3. from Induction due to Electrical lines. 4. from diggings by different agencies. 5. from damages while handling.

APPLICATIONS OF OPTICAL FIBER CABLE Optical fiber transmission systems are widely used in the backbone of networks. Current optical fiber systems provide transmission rates from 45 Mb/s to 9.6 Gb/s using the single wavelength transmission. The installation cost of optical fibers is higher than that for co-axial or twisted wire cables. Optical fiber are now used in the telephone systems. In the local area networks (LANs). 5. 8 MB MUX for 120 channels. 6. 34 MB for 480 channels. 7. 140 MB for 1920 channels.

ADVANTAGES OF OPTICAL FIBERS Small Size and Light Weight: The size (diameter) of the optical fiber is very small. Therefore, a large number of optical fibers can fit into a cable of small diameter. Easy availability and low cost: The material used for the manufacturing of optical fibers is silica glass. The material is easily available. Hence , the optical fibers cost lower than the cables with metallic conductors. No electrical or Electromagnetic interference: Since the transmission takes place in the form of light rays the signal is not affected due to any electrical or electromagnetic interferences. Large bandwidth: As the light rays have high frequency in the GHz range, the bandwidth of the optical fiber extremely large.

DISADVANTAGES OF FIBER CABELS Sophisticated plants are required for manufacturing optical fiber. The initial cost incurred is high. Joining the optical fiber is a difficult job.

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