THORLABS Redstone OSA305, Руководство пользователя

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Optical Spectrum Analyzers Chapter 7: Software
Rev D, June 16, 2022 Page 26
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Envelope : Only available in Interferogram view. Traces with this option will be updated as the envelope
of the last acquired interferogram from the selected detector. This trace will be updated on each
acquisition of an interferogram.
If the calculation of a trace cannot be performed, e.g., if the two input traces have different lengths, the Trace
Label background will be red and the reason for the error will be displayed in a popup when hovering over the
Trace Label with the mouse pointer.
7.4. Saving and Loading Data
7.4.1. Saving Data
When the “Save All” option has been selected, only traces in the current view (Spectrum view or Interferogram
view) will be saved.
7.4.2. Loading Data
If the software is currently running in Spectrum view and the loaded trace is an interferogram, the view will be
switched to Interferogram view automatically. Likewise, will a spectrum loaded while in Interferogram view
switch to Spectrum view.
7.5. Analyzing Data
Since the OSA20xC and Redstone OSA305 collect interferograms, the two left-most analysis tools are available.
The other analysis tools are described in the ThorSpectra User Guide.
7.5.1. Wavelength Meter
The Wavelength Meter analysis tool very accurately determines the wavelength of the input light to the
spectrometer. This analysis is only available for light from sources with a bandwidth of 10 GHz or less. This tool
works by analyzing the periodicity of the collected interferograms before apodization is performed. The number
of cycles in the interferogram are counted and compared to the number of cycles in the interferogram of the
built-in reference laser (see Section 4.1 Introduction).
When the Wavelength Meter tool is enabled, the analysis results are displayed in a floating window or docked
to the main display area. The calculated wavelength is displayed in the currently set x-axis spectral units. If the
input light does not have sufficiently narrow linewidth for the analysis to work properly, the text “Invalid Value”
will be displayed instead of a number. The calculated wavelength is displayed with an accuracy that corresponds
to the estimated error in the measurement. If the source shows multimode behavior, the number of significant
decimals displayed will be reduced to reflect the reduced precision of the measurement. The analysis estimates
the error in the measured wavelength, displaying the significant digits in black and the not significant digits in
gray. The control “Decimals” in the options panel makes it possible to manually set the number of decimals to
display.
The tool window shows the minimum, maximum, mean, and standard deviation of the wavelengths that have
been measured while the wavelength meter tool has been active. The values are updated after every new
sweep. The statistics can be reset by clicking the “Clear” button.
Figure 23. Wavelength Meter Window
Note that the wavelength metering is performed on the interferogram during the collection process prior to
apodization and it is not necessary to turn off the apodization for this analysis tool to function.