3-17
IM AQ6370D-01EN
Preparing for Measurement
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App
Index
Summary of usable optical fiber types and usage limitations
Optical Fiber Type
Obtained Wavelength
Absolute Level
Resolution (in nm)
Accuracy
Type Core Diameter
SM 5
0.020
NG
SM 9.5
0.020
OK
GI
50
0.050
NG
GI
62.5
0.050
NG
SI
50
0.050
NG
SI
80
0.100
NG
SI
100
0.200
NG
SI
200
0.500
NG
SI
400
1.000
NG
SI
800
2.000
NG
Level Accuracy below the Cutoff Wavelength (Short Wavelength) of a
Connected Optical Fiber
With wavelengths at or below the cutoff level of the connected fiber, light propagates
through the optical fiber in multiple modes. When high-coherent light from a light source
such as a gas laser or DFB-LD light source propagates in multiple modes, speckle noise
contained in the optical fiber output light may become unstable by the optical fiber’s form,
resulting in an inaccurate measurement level.
In such cases, improving the coupling between the light source and the optical fiber will
lessen the level inaccuracy.
3.6 Alignment Adjustment
