Testing & Commissioning Optical Fiber Link -Part 2

Testing & Commissioning Optical Fiber Link -Part 1 HERE

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More Examples on Calculation of Optical Power Budget

Assuming our Multimode Fiber Optics cabling configuration as below :

As per Singlemode, there are 2 common operating wavelength namely 850nm and 1300nm.
The respective attenuation or loss as illustrated below :

Figure 2 : Operating Wavelength Attenuation

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Please refer to the following link for calculation of optical fiber budget formula :-
Testing & Commissioning Optical Fiber Link -Part 1 HERE

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Optical Power Budget Calculation
Using above Figure 1 fiber optics schematic diagram followings can be deduced :
a. Total length of fiber is 1km (please use OTDR to measure actual fiber length)
b. 2 nos of splicings
c. 2 nos of connectors
d. MM operating wavelength of 850 nm - 3dB/km, 1300nm - 1dB/km

Operating Wavelength at 850nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss
= (1 km x  3 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 4.4dB
Operating Wavelength at 1300nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss
= (1 km x 1 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 2.4dB

• As such, when we do actual measurement using power meter & light source the measured loss must be less than the calculated allowable maximum loss. 
• If the actual measurement value is higher than calculated maximum loss then most likely there will no communication or transfer data between Station A and Station B.​

On next articles  we will emphasized on

• Calculating budget loss if there are jointings or splicings between fiber optics cable 
• Calculating budget loss if few fiber optics cable are connected via connectors