Hello,
Today I will share with you the calculation of optical fiber attenuation in FTTH access engineering.
Attenuation limit: Psr = La × αf + Mc + Pp + nAc
Among them: attenuation between Psr S point and R point (including power amplifier)
n Number of active connectors (including ODF of this station and ODF of intermediate jumper station)
Ac active connector attenuation, take 0.3dB
Pp optical channel cost, take 1dB
Mc optical cable richness, take 3dB
αf optical cable attenuation, take 0.22dB/Km (1550nm) (including joint loss)
La relay transmission length (Km)
Dispersion limit: D=LD×18ps/nm.Km (1550nm)
In actual engineering, the long-distance transmission of optical signals requires that the signal power is sufficient to offset the attenuation of the fiber. The attenuation coefficient of the g.652 fiber at the 1550nm window is generally about 0.25db/km, taking into account factors such as optical connectors and fiber redundancy. The comprehensive fiber attenuation coefficient is generally less than 0.275db/km
In daily maintenance, in the 1550 wavelength mode, every kilometer is calculated as 0.25, and each dead joint wears 0.5; the live joint is also calculated as 0.25
Calculation method of the optical power of the relay section: total attenuation of the relay section = 0.3 ~ 0.4db/km × fiber length + loss of the optical fiber active connector + transmission richness (reserved margin for increased loss for future maintenance and aging, generally 2 ~ 6db)
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