Figure 5-4. Example Of Power Dependence And Pulse-To-Pulse - NORTHROP GRUMMAN Patara I User Manual

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Laser Optimization sheet. Vary the chiller temperature and enter values in the
Chiller Temperature excursion table.
4. Peak up the laser power by tuning the temperature of the TEC controller.
Beginning with the TEC Temperature from the ATP Test Report Data
Summary, adjust the temperature up and down to optimize.
WARNING.
To prevent damaging the HM mirror and LBO crystal, the laser output
power should not decrease more than 10% when adjusting the TEC Temperature.
The phase matching of the second harmonic generation (SHG) crystal is crucial
for the Patara laser. This is achieved by setting the proper temperature on the
SHG crystal, which is controlled by the TEC controller inside the eDrive.
Figure 5-4 illustrates an example of the dependences of power and pulse-to-pulse
instability of the laser to the SHG crystal temperature. As shown in the example,
the mid-point of the temperature band is around 28.5°C. The laser may have peak
power at 29.3°C in this example, but a small temperature change on the SHG
could result in a power fluctuation.

Figure 5-4. Example of Power Dependence and Pulse-to-Pulse

Instability of the Laser to SHG Crystal Temp.
5. Peak the laser power by increasing the current.
Figure 5-5 illustrates an example of the dependence of the output power and
pulse-to-pulse instability of the Patara laser to operating current. Notice that the
laser power increases as the operating current is increased. The laser reaches peak
power around 23 A. Search for the peak power by changing the current 0.1 A
increments around the operating current. Once the peak power is found, lower the
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Chapter Five: Maintenance
Patara I and II Laser User Manual