YASKAWA AQ6370B - Page 220

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IM 735302-01E
Analysis
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App
Index
Absolute Level Accuracy
Theinstrument’sabsoluteleveliscalibratedwitha9.5μmsingle-modeopticalfiber.
In terms of actual capability, even single-mode optical fibers that do not have a core
diameterof9.5μmprovidenearlythesamelevelofaccuracy.
Multimode (GI) fiber provides a relatively accurate spectrum if the light source is low-
coherent light such as white light, natural light, or an LED. If the light source has high
coherency as in the case of a laser beam, interference will occur inside the optical fiber,
and the intensity distribution of light radiating from the fiber tip will vary according to the
fiber form. As a result, the spectrum (measurement level) may fluctuate if the fiber is
moved.
When an optical fiber with a large core diameter or large NA value is used, a low fraction
of the light emitted from the optical fiber is received. Therefore, the measurement level is
lower than the true value, but the optical spectrum is accurate in relative terms.
WL SHIFT **.**nm
This key is used to set the wavelength shift.
When the wavelength shift is changed, the set value is added to the display value on
the wavelength axis. This key is used for purposes such as correcting differences in
wavelength display values among different measurement instruments.
The setting range is -5.000 to 5,000 nm. Settings can be adjusted in steps of 0.001 nm.
The value changes in steps of 0.1 nm if you press the COARSE key.
When setting the wavelength shift amount, is displayed at the bottom of the screen
in inverse video.
LEVEL SHIFT***.***dB
This key is used to set the level shift.
When the level shift is changed, the set value is added to the display value on the level
axis.
This key is used for purposes such as correcting level errors due to differences in the NA
valuesof9.5/125μmSMopticalfibersconnectedtotheinstrument,andcorrectingloss
on externally connected isolators, filters and the like.
The setting range is -60.00 to 60.00 dB. Settings can be adjusted in steps of 0.01 dB.
The value changes in steps of 0.1 dB if you press the COARSE key.
When setting the wavelength shift amount, is displayed at the bottom of the screen
in inverse video.
7.14 Correcting Displayed Values