3.6.1.3 Rayleigh Scatter
Rayleigh scatter occurs when there are small changes in the
refractive index of materials in which the light signal travels, this loss is
caused by the miniscule variation in the composition and density of the optical
glass material itself.
Figure 19 Rayleigh Scatter loss, The light can also be loosed
into the cladding or back scattered light that are caused by obstacle like
bunching of atoms in the core of the fiber .
3.6.1.4 Bending Loss
Bending losses occurs when a cable is bent and it disrupts the
path of the light signal the tighter the bends of a cable the greater it is of
the light loss.
Bending losses occurs here at those points
Figure 20 . Bending loss
Figure 20 shows the bending radius of an optical fiber that
result in light displacement caused by pinching or squeezing the fiber. Bending
deform the fiber's core slightly causing light to escape at these deflections,
The bend curvature creates an angle that is too sharp for the light to be
reflected back into the core and some of it escapes through the fiber cladding
hence the result is the optical power loss which increases rapidly as the
radius is decreased to an inch or less.[20]
3.6.1.5 Insertion Loss
Insertion loss is the most important performance indicator of
a fiber optic interconnection. this is the loss of light signal, measured in
decibels (dB) during the insertion of a fiber optic connector. Some of the
common causes of insertion losses includes: the misalignment of ferrules during
connection, the air gap between two mating ferrules and absorption loss from
impurities such as scratches and oil contamination
Insertion loss can be minimized by proper selection of
interconnect materials ,good polishing and termination process of fiber
connectors. [19]
3.6.1.6 Return Loss
Return loss which is also known as back reflection is the loss
of light signal that is reflected back to the original light source. this
occurs as the light is reflected off the connector and travels back along the
fiber to the light source It occurs also when there are changes in the
refractive index of materials in which the light travels such as the fiber core
and the air gap between fiber interconnection. When light passes through these
two different refractive indexes some of the light signal is reflected back.
[19]
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