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Kishori Sharan MathurResearch Scholar, Shri JJT
University,Jhunjhunu 333001, Rajasthan,
[email protected]
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Attenuation
- Absorption, Scattering
Dispersion
- Modal, Chromatic, PMD
Nonlinear effects- SPM, XPM, FWM, SBS, SRS
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Attenuation
Dispersion
Nonlinearity
Waveform After 1000 KmTransmitted Data Waveform
Distortion
It May Be a Digital Signal, but Its Analog Transmission
THE DIGITAL SIGNAL IS CARRIED USING ANALOG CARRIER SIGNAL (LASER
OR LED)
AND THE TRANSMISSION MEDIA IS NOT IDEAL
THE DATA CARRIED OVER OPTICAL SIGNAL IS
MOSTLY DIGITAL AND HIGH SPEED
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Attenuation:
Reduces power level with distance
Dispersion and nonlinear effects:
Erodes clarity with distance and speed
Noise and Jitter:
Leading to a blurred image4
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z=0 z=L
Dispersion
z=0 z=LAttenuation
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800 900 1000 1100 1200 1300 1400 1500 1600
Wavelength in Nanometers (nm)
0.2 dB/Km
0.5 dB/Km
2.0 dB/Km
Attenuation vs. Wavelength S-Band:14601530nm
L-Band:15651625nm
C-Band:15301565nm
Fibre Attenuation Curve
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a
monomodefiber
800 1000 1200 1400 1600wavelength / nm -->
1. window 2. window 3. window
Rayleigh scattering
1/l4
10
1
0.1
IR absorption
attenuatio
ncoefficient/dB/km-
->
multimode
fiber
Rayleigh scattering unavoidable loss mechanism
scattering in all directions
wavelength dependent
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ATTENUATION IN OPTICAL FIBERS
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INTRINSIC ABSORPTION
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RAYLEIGH SCATTERING
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BENDING LOSSES IN FIBERS
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A FIBER CURVATURE(BEND)
RESULTS IN MACROBENDING
LOSS OF SIGNAL LOSS OF OPTICAL
SIGNAL DUE TO BEND
SENSOR
FIBER
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MFD AT
1300nm 1550nm 1625nm
FIBERS HAVEING LARGE MFD ARE MORE SENSITIVE TO BENDINGS
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TYPICAL ATTENUATION COEFFICIENT FOR BENT AND UNBENT FIBER
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Fiber with no bending
THE EFFECTS OF MACRO BENDING ON A FIBER
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