2-7
Making Measurements
Using the Agilent83430A
Testing dispersion power penalty
Signal degradation due to fiber dispersion can have a major impact on the
maximum distance over which optical data can reliably be sent. The disper-
sion power penalty of single-mode fiber can be tested with the measurement
setup shown in the following figure. The following equipment is used:
•Agilent 83430A
•Agilent 8153A optical power meter
•Agilent 11890A Option H01 optical coupler
•Agilent8156A variable optical attenuator
•Agilent71603B error performance analyzer
The system is first tested with a 1 meter length of fiber. Use the attenuator to
adjust the received power until the desired BER is measured. Substitute a
long length of fiber for the 1 meter fiber and adjust the attenuator to achieve
the desired BER. The difference in received power is the disper sion power
penalty. The Agilent83430A can be used as a reference source to isolate sys-
tem component causes of undesired dispersion power penalty results.
The Agilent 83430A is an excellent choice for this measurement because i t has
a very narrow modulated spectral width (low chirp) and meets the SDH /
SONET dispersion power penalty requirement at 1200 ps/nm fiber disper sion.
Lower dispersion power penalty lasers are available as special options.