5-2
IM AQ6370E-02EN
5.2 Inspection of Level Accuracy
Perform a check of the instrument’s level accuracy. Use a light source with a wavelength of either
1310 nm or 1550 nm.
Light source
Optical power meter
9.5/125 μm SM optical fiber
AQ6370E
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 9.5/125 µm SM optical fiber and turn the light
source ON.
3.
Press
SWEEP
. The SWEEP menu is displayed.
4.
Tap the
Auto
. The spectrum of the light source is automatically measured.
5.
When automatic measurement is complete and REPEAT sweep begins, press SETUP.
6.
Tap the
Resolution
. The RESOLN menu is displayed.
7.
Tap the
More
repeatedly until the More 2/2 menu is displayed.
8.
Tap the
2nm
.
9.
Press
PEAK SEARCH
then measure the peak level of the waveform.
10.
Remove the SM optical fiber from the instrument and connect the light source to an optical
power meter.
11.
Use the optical power meter to measure power values of the light source.
12.
Check that peak level values obtained in step 9 agree with the ones obtained by the optical
power meter (within the specified level accuracy). For information on level accuracy, see
chapter 6, “Specifications.”
Note
• For the light source, prepare a line spectrum light source such a gas laser or DFB-LD. 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 9.5/125 μm single-mode optical fiber (SSMA type in JIS C6835, with PC
polishing, 9.5 μm mode field diameter, and 0.104 to 0.107 NA). 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.
