2-2
IM AQ6370D-01EN
2.2 Measurement
Alignment Adjustment <<See section 3.6 for the operating procedure>>
This function allows adjustment of the optical axis of the instrument’s built-in
monochromator (spectroscope).
The instrument’s optical performance is not guaranteed until the alignment adjustment
function has been executed. Failure to perform this adjustment can result in distortion
of measured waveforms. After alignment adjustment has been executed, wavelength
calibration is also subsequently performed automatically. If you are using the instrument
for the first time or using it after it has been severely shaken while being moved, perform
the alignment adjustment procedure after warm-up ends.
Wavelength Calibration <<See section 3.7 for the operating procedure>>
Wavelength calibration can be performed using the internal reference light source (when
the built-in light source specification is -L1) or an external light source.
Resolution Calibration <<See section 3.8 for the operating procedure>>
Typically the filter response of an optical spectrum analyzer is not rectangular, and
thus the resolution bandwidth differs slightly from the equivalent noise bandwidth. This
difference becomes prominent especially when the wavelength resolution is high (e.g.,
0.05 nm or less). The resolution calibration function measures the equivalent noise
bandwidth at each resolution setting and internally sets the resolution bandwidth to the
result. The resolution bandwidth appears in parentheses in each of the resolution soft
keys on the resolution screen. The resolution bandwidth accuracy affects the results of
noise measurements and the results of optical power measurements of wideband light
sources. In detail, the resolution bandwidth is used when the following analysis and
computation functions are executed. For details, see pages 3-25 and 3-26.
• WDM analysis
• EDFA-NF (optical amp gain, NF measurement)
• Power analysis
• OSNR and total power of DFB-LD analysis
• Total power of FP-LD analysis
• Total power of LED analysis
• Power density markers, Integrated power markers
Auto Measurement <<See section 5.1 for the operating procedure>>
This function automatically sets the optimal measuring conditions for the input light and
displays the spectrum waveform. This function is useful when the characteristics of the
input light are not well known.
The wavelength range of input light that can be auto-measured is 1200–1670 nm.
The measurement conditions that are set automatically are as follows.
1. Span (SPAN)
2. Center wavelength (CENTER)
3. Reference level (REF LEVEL)
4. Resolution (RESOLUTION)
Other measuring conditions (sensitivity, averaging times, number of sampling points,
and interval settings) are set to their defaults. The horizontal and vertical axes of the
displayed spectrum waveform are zoomed to an appropriate degree.
Single Sweep <<See section 5.13 for the operating procedure>>
This function executes a single sweep or forcibly stops a sweep operation.
