This document discusses attenuation in optical communication systems. It defines attenuation as the reduction in amplitude of a signal as it propagates through an optical fiber. Attenuation is usually measured in decibels (dB). The document outlines how to calculate attenuation loss and the attenuation coefficient using the input and output power and length of the fiber. It also lists several factors that can cause attenuation, including material absorption, scattering losses, and different types of dispersion.

1. Aattenuation of Signal
By Prof. Hitesh Dholakiya
Engineering Funda YouTube Channel
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2. Outlines of Attenuation
• Basics of Attenuation
• Attenuation calculation
• Attenuation Factors
• Attenuation Coefficient
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Optical Communication YT Playlist

3. Basics of Attenuation
 Attenuation represents the reduction in amplitude of signal
 It is called as the transmission loss and it represents the reduction in
intensity of the light rays propagating through it.
 It is measure with respect to the distance travelled by light rays in
optical cable.
 Attenuation is usually expressed in decibel (dB).
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Engineering Funda Android App
Optical Communication YT Playlist

4. Attenuation Calculation
Attenuation loss 𝛼𝐿 (dB) is calculated by
𝛼𝐿 = 10 log
𝑃𝑖
𝑃𝑜
Where,
 𝛼𝐿 = Attenuation loss in dB
 𝑃𝑖 = Input Power
 𝑃𝑜= Output Power
 Attenuation Coefficient 𝛼(dB/km) is calculated by
𝛼 =
10
𝐿
log
𝑃𝑖
𝑃𝑜
Where,
 L = Length of Fiber Cableel
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5. Attenuation Factors
Attenuation produces losses in the system. Different factors as follows
 Material Absorption
 Intrinsic
 Extrinsic
 Linear Scattering Losses
 Non Linear Scattering Losses
 Stimulated Raman Scattering Losses
 Fiber Banding Losses
 Dispersion
 Chromatic Dispersion
 Material Dispersion
 Waveguide Dispersion
 Intermodal Dispersion
 Polarized mode Dispersion
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