Anritsu MS9740B - Page 57

2.7 Precautions at Measurement
2-15
2
Before Use
Figure 2.7-1 Difference in light radiated from optical fibers
Effect of Water Vapor on Spectrum Absorption
Water vapor (OH radicals) in air have multiple absorption spectra around
1350 to 1450 nm. If there is water vapor in the MS9740B, ripple will be
observed in the measured spectrum due to the water vapor absorption
spectra. The size of the ripple changes with humidity. If the measurement
results are being impacted by water vapor absorption spectra, use the
MS9740B in a low-humidity/dry environment.
Figure 2.7-2 Water Vapor Absorption Spectrum
SM Fiber
GI Fiber
NA 0.1
NA 0.2
Loss part at
input to main
frame
Part measured
by main frame
Loss (dB)
Wavelength (nm)