2-4
IM AQ6373-01EN
Power Density Display <<See section 5.2 for the operating procedure>>
The power per 1 nm is called the power density.
The level axis of the AQ6373 indicates the absolute power per wavelength resolution.
For example, if the resolution is set to 0.1 nm, the power per 0.1 nm will be displayed.
Since the optical spectrum of such devices as a gas laser or a laser diode is narrower
than the wavelength resolution of the instrument, the entire power is accommodated
within the band of a resolution. Therefore, the measured power (peak level) is equal
to the total power of the light source. This instrument has been calibrated to display
accurate power under such conditions.
On the other hand, natural light or lights such as fluorescent lamps or LEDs, have,
in many cases, optical spectrums wider than the wavelength resolution set for the
instrument. Therefore, if the instrument measures these lights, measured power will vary,
depending on the resolution setting.
In order to deal with this issue, the instrument is equipped with the dBm dBm/nm soft key
to allow the level axis displays to switch from the absolute power (dBm, mW, μW, nW,
pW) per resolution to power density (dBm/nm, mW/nm, μW/nm, nW/nm, pW/nm).
In the case of power density displays, a measured value is converted to power per 1 nm.
Therefore, whatever resolution is used for measurement, certain measured values will
always be available.
For information on the use of dBm and dBm/nm, see “Power Density Display” in section
5.2, “Horizontal/Vertical Axis Settings.”
Note
Specifications such as level accuracy, measurement level range, and level linearity of the
instrument are provided for the absolute power display.
Pulse Light Measurement <<See section 5.14 and 5.15 for the operating
procedure>>
The following three methods are available for measuring pulse light.
• Measurement using Peak hold mode
• Measurement as a time average spectrum .
• Measurement using External trigger mode.
2.2 Measurement