Reach And Optical Link Budget; Reach Calculation Examples - Avaya 8800 Planning And Engineering, Network Design

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Reach and optical link budget

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Reach calculation examples

Reach and optical link budget
The absorption and scattering of light by molecules in an optical fiber causes the signal to lose
intensity. Expect attenuation when you plan an optical network.
Factors that typically affect optical signal strength include the following:
• optical fiber attenuation (wavelength dependent: typically 0.20 to 0.35 dB/km)
• network devices the signal passes through
• connectors
• repair margin (user-determined)
The loss budget, or optical link budget, is the amount of optical power launched into a system that
you can expect to lose through various system mechanisms. By calculating the optical link budget,
you can determine the transmission distance (reach) of the link (that is, the amount of usable signal
strength for a connection between the point where it originates and the point where it terminates).
Important:
Insertion loss budget values for the optical routing system CWDM OADM and OMUX include
connector loss.
Reach calculation examples
The examples in this chapter use the following assumptions and procedure for calculating the
maximum transmission distances for networks with CWDM components.
The examples assume the use of the values and information listed in the following table. Use the
expected repair margin specified by your organization. For SFP, SFP+, XFP, and multiplexer
specifications, see Avaya Ethernet Routing Switch 8800/8600 Installation — SFP, SFP+, XFP, and
OADM Hardware Components (NN46205-320). Multiplexer loss values include connector loss.
Attenuation of 0.25 dB/km is used, but the typical attenuation at 1550 nm is about 0.20 dB/km.
Ensure that you use the appropriate value for your network.
June 2016
on page 47
on page 47
Planning and Engineering — Network Design
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Transmission distance
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