Starting A Measurement; Sensitivity And Resolution - THORLABS Redstone OSA305 Quick Start Manual

Redstone™ OSA305
Chapter 3: Using the OSA
3.4.

Starting a Measurement

Once the OSA is connected to the PC, the OSA name will appear to the left on the
Settings bar. It can also be found in the list of available devices shown by clicking
the "Devices" button, found under the Instrument menu.
The GUI can assist with selecting acquisition settings suitable for the input source.
Clicking the "Auto setup" button under the Instrument menu will start an automated
process, which will try to determine the nature of the input source and apply
suitable settings.
A measurement is started by clicking the "Single" or "Repeat" buttons under the
Instrument menu, see Figure 3. Information such as gain level etc. is displayed in
the Status bar at the bottom of the screen.
Figure 6 The Trace Drop Down menu, with the Average option marked
It is possible to average multiple spectra, which normally reduces noise levels of
the measurement. It can therefore be beneficial to average a few spectra if the
intensity of the incoming light is low. The averaging is selected under the Trace
drop down menu (see Figure 6); here it is also possible to select the number of
sweeps to include in the average.
3.4.1.

Sensitivity and Resolution

The Redstone OSA305 instrument can be set to one of four resolution settings:
High, Medium High, Medium Low, or Low, which correspond to resolutions of
-1 -1 -1
2.0 GHz (0.0625 cm ), 7.5 GHz (0.25 cm ), 30 GHz (1.0 cm ), and 120 GHz
-1
(4.0 cm ), respectively. The available sensitivity settings are High, Medium, and
Low, corresponding to different speeds of the moving mirror inside the instrument
and controls the number of available detector gain levels. The trade-off is between
higher measurement update frequency, and higher resolution and increased
sensitivity. It is recommended to start in Low Resolution and Low Sensitivity to find
coarse settings of the trace followed by higher resolution measurements, if
needed.
Rev B, December 15, 2021 Page 9