1-6
IM AQ1210-01EN
1.2 Optical Pulse Measurement (OTDR)
The instrument applies an incident optical pulse to the connected optical fiber cable and measures
the power level of the reflected light from the different sections of the optical fiber cable such as its
connections, bent sections, and the open end of the fiber. The instrument uses the measured power
level to determine the distance to the different points (splices, breaks, etc.) of the optical fiber cable
and the loss and other phenomena that occur at those points. For details on how to view optical pulse
waveforms, see section 1.3.
Reflection point
Optical fiber cable being measured
Optical pulse output
Reflected light
Do not bend the optical fiber cable.
OTDR/light source port
AQ1210A, AQ1215A,
AQ1210E, AQ1215E,
AQ1215F, AQ1216F
Real-time Measurement
Real-time measurement is a feature that measures optical pulses while updating and displaying
the measured values. You can monitor in real time events, such as splice loss and return loss,
while installing optical fiber cables. You can also view the changes in the waveform as you change
the measurement conditions, such as the wavelength, distance range, and pulse width. Real-time
measurement is not possible in MAP mode (the mode is automatically switched to TRACE mode
before making a measurement).
Averaged Measurement
Averaged measurement is effective when you want to detect reflections, splice loss, and other faint
events that are generated from connections or splice points but are buried in noise. The instrument
derives the measured data by averaging the specified number of optical pulse measurements or by
averaging optical pulse measurements over the specified duration. During averaged measurement,
you cannot change the measurement conditions. You can stop an averaged measurement before it
completes.
• Multi Wavelength Measurement
Two wavelengths, 1310 nm and 1550 nm, can be measured with one measurement operation.
When a measurement is started, an averaged measurement is performed at 1310 nm. Then, the
wavelength is automatically switched to 1550 nm, and another measurement is made.
Auto Check before Measurement
• Fiber-In-Use Alarm
The instrument uses the same wavelength that is used in real communication to measure optical
pulses. If communication light is present in the optical fiber cable that you want to measure, the
communication will be affected. When this communication light is present, we say that the fiber is
in use. The fiber-in-use alarm is a feature that checks if communication light is being transmitted
along the optical fiber cable that you are trying to measure. If the fiber is in use, a warning
message is displayed asking whether you want to continue the measurement.
• Connection Check
The connection check is a feature that checks the state of the connection between the
instrument and an optical fiber cable. When this feature is set to on, you can prevent light from
being transmitted from the instrument OTDR port if an optical fiber cable is not connected to the
instrument or if the cable is not connected correctly.
