Manual

 Fiber-to-the-Antenna (FTTA) Installation and Maintenance Testing
Fiber Attenuation Overview
Injection
loss
Absorption
loss
Scattering
loss
Micro
Bending
loss
Macro
Bending
loss
Coupling
loss
Junction
loss
Output
Impurities
Input
Microbending occurs when the fiber core deviates from the axis. It can be caused by manufacturing defects,
mechanical constraints during the fiber laying process, and environmental variations (temperature, humidly or
pressure) during the fiber’s lifetime. Typical causes include freezing water causing external pressure or sharp objects
impeding the fiber.
Macrobending is caused by physical bends in the fiber that exceed fiber bend-radius limitations (more than a 2 mm
radius). Typical causes are poor installation or loading of fiber into BBU/RRU enclosures, fiber trays or junction boxes,
and tampering. Optical signal level attenuation due to macrobending increases with wavelength. For example, a
signal travelling at 1550 nm will attenuate more than a signal travelling at 1310 nm in the presence of a bend.
Macrobends, typically found in RRU enclosures, junction boxes, and fiber trays.
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