Changing The Oscilloscope Display Units To Watts Of Optical Power - Agilent Technologies 11982A Operation And Service Manual

Time-Domain Measurements

Changing the Oscilloscope Display Units to Watts of Optical Power

Changing the Oscilloscope Display Units to
Watts of Optical Power
Since an oscilloscope displays voltage, a conversion factor must be used so the
oscilloscope read out is in watts. For the oscilloscope to display optical power,
the voltage responsivity (also called the conversion gain) of the
Agilent 11982A must be taken into account. The probe attenuation field is not
available with some oscilloscopes. The oscilloscope display can still be con-
verted to watts by dividing the oscilloscope's reading (in volts) by the respon-
sivity.
To change the oscilloscope's display units to watts, you must perform the fol-
lowing steps:
1 Determine the responsivity of your Agilent 11982A for the wavelength of the
source. The responsivity of the Agilent 11982A is on the Agilent 11982A
Calibration Chart shipped with your instrument and shown in
page 3-5. The responsivity is calibrated at two wavelengths: 1300 nm and
1550 nm.
2 Determine the reciprocal of the responsivity.
3 Enter the reciprocal of the responsivity in the oscilloscope's probe attenuation
field.
3-4
Figure 3-1 on