10-6
IM AQ6373-01EN
10.5 Inspection of Level Accuracy
Perform a check of the instrument’s level accuracy. Use a light source of 850 nm.
AQ6370
OPTICAL SPECTRUM ANALYZER
Light source
Optical power meter
AQ6370B
9.5/125
µ
m SM optical fiber
Procedure
1.
Execute the alignment adjustment function on the unit’s internal monochromator.
For details, see section 3.5, “Alignment Adjustment.”
2.
Connect the light source and instrument with a 5/125
µ
m SM optical fiber and turn
the light source ON.
3.
Press
SWEEP
.
4.
Press the
AUTO
soft key. The spectrum of the light source is automatically
measured.
5.
When automatic measurement is complete and REPEAT sweep begins, press
SETUP
.
6.
Press the
RESOLUTION
soft key then set the instrument’s wavelength resolution
to 1.000 nm.
7.
Press
PEAK SEARCH
or
MARKER
then measure the peak level of the
waveform.
8.
Remove the SM optical fiber from the instrument and connect the light source to
an optical power meter.
9.
Use the optical power meter to measure power values of the light source.
10.
Check that peak level values obtained in step 7 agree with the ones obtained by
the optical power meter (within the specified level accuracy). For information on
level accuracy, see chapter 11, “Specifications.”
Note
• Please use a light source with a spectrum width of less than 1 nm, such as a gas laser or
DFB-LD.
• Connect the light source with the unit via the 5/125 mm SM optical fiber. Then, turn on the
light source. If a wide spectrum light source is used, the power measurements may not be
accurate.
• The level measurement error of the instrument changes as shown in the figure below,
according to the numerical aperture (NA) of the optical fiber connected to the input
connector. The instrument’s absolute level is calibrated using a 5/125 μm single-mode
optical fiber (0.14 NA typ.). Even if a single-mode optical fiber is used, the level accuracy will
be outside the specifications if the NA is not in the range shown above.