NORTHROP GRUMMAN Patara I User Manual

Contents

NORTHROP GRUMMAN Patara I User Manual Manual pdf 57 page image

Chapter Five: Maintenance© 2018 Cutting Edge Optronics, Inc. 45 Patara I and II Laser User ManualLaser Optimization sheet. Vary the chiller temperature and enter values in theChiller 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 DataSummary, adjust the temperature up and down to optimize.WARNING. To prevent damaging the HM mirror and LBO crystal, the laser outputpower should not decrease more than 10% when adjusting the TEC Temperature.The phase matching of the second harmonic generation (SHG) crystal is crucialfor the Patara laser. This is achieved by setting the proper temperature on theSHG 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-pulseinstability 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 peakpower at 29.3°C in this example, but a small temperature change on the SHGcould result in a power fluctuation.Figure 5-4. Example of Power Dependence and Pulse-to-PulseInstability 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 andpulse-to-pulse instability of the Patara laser to operating current. Notice that thelaser power increases as the operating current is increased. The laser reaches peakpower around 23 A. Search for the peak power by changing the current 0.1 Aincrements around the operating current. Once the peak power is found, lower the