HP 8163A Series, User Manual

Page: 70 / 207

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Power Measurement
How to Measure Power
How to Set the Wavelength
This is the wavelength value. The responsivity of the Power Meter
varies with wavelength. For accurate power measurement, you need
to input the wavelength of the optical input. To set the wavelength
to 1545.000 nm:
1 Move to the Power Meter channel and press the [Details]
softkey.
2 Move to the [
λ]
parameter and press E
NTER
.
3 Enter 1545.000 and press Enter.
How to Remove Electrical Offsets
Optical Power Meters measure optical power by converting optical
power to electrical power, and then measuring electrical power. An
electrical offset is electrical power that is always present, even if
there no optical power is input. If electrical offsets are not removed,
they affect the accuracy of power measurement.
N OT E The environmental conditions and the temperature of the instrument
affect electrical offset. For the best results you must:
• Allow the instrument time to acclimatize (around 24 hours).
• Allow the instrument time to warm up (around 20 minutes).
• Make sure that the optical input is not receiving any light. If you are
using multi-mode fiber-optic cable, you must disconnect the cable
and cover the input to the Power Meter to perform a zero.
It is good practice to zero the instrument before making any important
measurements.
To remove electrical offsets:
1 Make sure the optical input is not receiving any light. If the
instrument has just been switched on, wait until SETTLING is
not displayed for the module channel.
2 Move to the Power Meter channel and press the [Menu] softkey.