Do you know why the phone signal gets weaker during the rain sometimes and we are not able to call or use the internet connection? This is because our phones communicate by transmitting the electromagnetic waves through the networks on the antennas which are called base stations. Due to the rain this communication is disturbed and we are not able to use the services. Is there any solution for this problem? Yes, if we use the optical fibre for transmitting the signal then the outside condition will not affect the communication. Let's see what optical fibre is !
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Optical fibre is a hair-like flexible and transparent fibre which is used for the transmission of data signals over large distances with a higher speed. Hence optical fibre is used to provide the service of internet, telephone and television etc. Optical fibre works on the principle of total internal reflection.
The optical fibre is made of various glass and plastic materials. Basically the optical fibre is consist of the following components-
As discussed above, the optical fibre works on the principle of total internal reflection. When a light beam travels in an optically denser medium and reaches the boundary it gets refracted with a larger angle than the angle of incidence (case 1). Now if we increase the angle of incidence the refractive angle will also increase (case 2). When we reach a maximum angle at which the refractive ray grazes parallel to the boundary (case 3). This angle is called the critical angle (ic). If we incident a ray on the boundary inside the denser medium, at an angle greater than the critical angle then it reflects back to the same medium (case 4). It is called the total internal reflection of light.
This phenomenon of total internal reflection is used to transmit the light through an optical fibre. As the core has a higher refractive index than that of the cladding, light signals continuously strike on the boundary of the core at an angle equal to or greater than the critical angles and then the cladding reflects it back to the core. This process goes on along the entire distance of signal transmission.
A fibre optics system consist of the following components
The optical fibre is classified based on the various parameters like material used, refractive index of the material and the propagation of light.
Glass and plastic are mostly used for the manufacturing of the optical fibre.
The classification is as follows -
Based on the propagation of light, optical fibre can also be classified as
The optical fibre is used in various industries and medical applications as -
Q1. What are the various advantages of optical fibre ?
A. Some of the advantages of using optical fibres are given below
Q2. Write various disadvantages of the optical fibre?
A. The disadvantages of optical fibre are
Q3. Write the difference between step index optical fibre and Graded index optical fibre?
A. The step index optical fibre has a separate core and cladding, core has greater refractive index than the cladding while the graded index optical fibre is made of single material with varying refractive index.
Q4. What are the factors that reduce the optical power during transmission?
A. In signal transmission there are few things which reduce the power of the signal. They are the absorption, scattering and the waveguide effect.
Q1. What is the speed of data transfer in optical fibre?
A. The speed of optical fibre is 1.6 Tb/s for field deployed systems and 10 Tb/s in lab systems.
Q2. What is the value of general loss in optical fibre?
A. The value loss is generally less than 0.3 db/km.
Q3. What bandwidth does the optical fibre have?
A. The optical fibre has the bandwidth 900 THz.
Q4. On which optical principle does the optical fibre work?
A. The optical fibre basically works on the principle of total internal reflection.
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