Agilent Technologies 86120C, User Manual

Page: 61 / 294

2-33
Making Measurements
Measuring Fabry-Perot (FP) Lasers
PWR The summation of the power in each of the selected peaks, or
modes, that satisfy the peak-excursion and peak-threshold
criteria.
The peak excursion and peak threshold settings define the laser modes
included in the measurement. Because the default peak excursion value
is 10 dB, measurement results normally include all laser modes within
10 dB of the peak response. Use the
PK THLD softkey to change the
number of laser modes used in the measurements. Refer to “Defining
Laser- Line Peaks” on page 2- 15 for information on the peak threshold
and peak excursion settings.
The peak excursion value (in dB) can also be used to determine which
side modes are included in the measurements. To be accep ted, each
trace p eak must rise, and then fall, by at least the p eak excursion
value about a given spectral component. Setting the peak- excursion
value too high results in failure to include the smaller resp onses near
the noise floor. Setting the value too low may cause unwanted
responses, including noise spikes, to be identified. Use
PK EXC to
change the peak excursion value.
Total Power
N
Σ
i 1 =
= P
i