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Entry   Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics Screenshot_2019-12-17_8_122311.pngScreenshot_2019-12-17_7_122157.png
    Reply   Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics cavity_polar_2e_etage_1kW.PNG
       Reply   Optical amplifier polarization state, posted by Ronic Chiche at Optical room about lasers and optics cavity_polar_3e_etage_2A_-_20kW.PNGcavity_polar_3e_etage_3A_-_30kW.PNGcavity_polar_3e_etage_3A_-_33kW.PNG
Message ID: 39     Entry time: Tue Dec 17 12:16:54 2019     Reply to this: 40
 Author: Ronic Chiche 
 Status: Fixed 
 Type: info 
 Category: lasers and optics 
 Location: Optical room 
 Title: Optical amplifier polarization state 

We placed a PBS + 2 photodiodes (PhD1, PhD2) at the output of the amplifier to check how the polarization of the amplifier changes with power.

example with 2nd stage @ 6A :
PhD1 = 24.7 mV
PhD2 = 8.9 mV
PhD1/PhD2 = 2.78

and with 3rd stage @ 2A :
PhD1 = 353 mV
PhD2 = 82.8 mV
PhD1/PhD2 = 4.26

Conclusion : we must adapt the quarter and half waveplates for each input power to be always matched with cavity polarization !!!
One could also study how the amplifier polarization changes during time and temperature.

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