1-5
IM AQ1200-01EN
Features
3
2
1
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Index
App
1.3 Waveform Display
You can display the measured result as a waveform on the screen. You can zoom the displayed
waveform and move the position that is displayed.
How to View Optical Pulse Waveforms
This section will explain the path of an optical fiber and the optical pulse measurement waveform.
The optical pulse applied to the optical fiber is reflected at different points of the optical fiber such
as its connections, bent sections, and the open end of the fiber. These sections generate loss. The
measured result is displayed as a waveform that has distance represented in the horizontal direction
and loss level represented in the vertical direction. On the waveform, detected points where loss or
reflection occurs are known as events.
Incident ray
Backscatter
Splice
Connector
Bend
Open end of
the fiber
Near-end
reflection
Splice loss
Approximated
line
Reflection caused
by a connector
Loss caused
by bending
Reflection at the open end
of the fiber (Fresnel reflection)
Dynamic range (SNR = 1)
Optical fiber
Near-end Reflection
This is the reflection that occurs at the point where the AQ1200 and the optical fiber are connected.
This also includes the AQ1200’s internal reflection. In the section where this near-end reflection is
detected, even if there are other connections, the loss and reflections that occur at these points cannot
be detected. This section is the near-end dead zone.
When you are measuring a short distance, connect a dummy fiber to reduce the effect of the near-end
reflection.
Backscatter
When light travels through an optical fiber, Rayleigh scattering caused by changes in the density of
materials that are smaller than the light’s wavelength and inconsistencies in the fiber’s composition
generates loss in the optical fiber itself. The portion of the scattered light that travels in the direction
opposite to the direction of propagation is known as backscatter.
Small
material
Incident ray
Backscatter
Optical fiber
