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Attenuation
Chapter 3 Optical TAPs
33
rev. 1

Transmit power from the network devices

Cable distance from the network device to the TAP

Maximum insertion loss from the TAP (see Table 5 )

Cable distance from the TAP to the analyzer

Analyzer port receive sensitivity

Other less crucial items that may also affect you include:

Number or quality of any connectors or patch panels in
the path to and from the TAP

Age of the fiber cables

Amount of heat in the environment where the fiber runs
In each split ratio, what you are dividing is the light power from the
incoming network link. The larger percentage of the light power is
used for the connection to the other network device and the smaller
portion is the light power for the analyzer. As long as there is
sufficient light power, all data is still sent to the analyzer regardless of
the split ratio chosen.
Table 5 Maximum insertion losses
Maximum Insertion Losses in Decibels
Multimode
50 micrometer Multimode
62.5 micrometer Single-Mode
9 micrometer
Split Ratio
1
1. The ratio is network/analyzer. So, a 70/30 connection has 70% of the light
power for the network and 30% for the analyzer.
1300nm 850nm 1300nm 850nm 1310-1550
50/50 3.5/3.5 4.7/4.7 4.5/4.5 5.5/5.5 3.6/3.6
60/40 3.0/5.0 3.8/5.7 3.7/5.6 4.7/6.6 2.8/4.8
70/30 2.3/6.3 3.0/7.0 2.9/7.0 3.9/8.0 2.0/6.1
80/20
2
2. Not recommended because too little light power reaches the analyzer.
1.7/8.3 2.4/9.0 2.3/9.0 3.2/10.0 1.3/8.0
90/10
2
1.2/12.0 1.9/12.5 1.8/12.8 2.7/13.5 0.8/12
Fiber Loss/km
3
3. Fiber loss is per kilometer of fiber.
1 3 1 3 0.4/0.3
Connector Loss .5 .5 .5 .5 .2