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Entry  Tue Jan 4 18:26:59 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
    Reply  Wed Jan 5 17:46:04 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
       Reply  Mon Jan 10 18:20:45 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
          Reply  Tue Jan 11 15:21:16 2022, Anchal, Update, BHD, PR2 transmission calculation LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPRS_Trans_Calc.ipynb.zip
             Reply  Thu Jan 13 17:10:55 2022, Anchal, Update, BHD, PR2 transmission calculation LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPR2_Trans_Calc.ipynb.zip
                Reply  Fri Jan 14 03:07:04 2022, Koji, Update, BHD, PR2 transmission calculation 
                   Reply  Fri Jan 14 11:00:29 2022, Anchal, Update, BHD, PR2 transmission calculation 
                      Reply  Fri Jan 14 13:46:25 2022, Anchal, Update, BHD, PR2 transmission calculation updated LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPR2_Trans_Calc.ipynb.zip
                         Reply  Wed Jan 19 16:22:48 2022, Anchal, Update, BHD, PR2 transmission calculation updated PR2transmissionSelectionAnalysis.pdfPR2_Trans_Calc.ipynb.zip
                            Reply  Thu Jan 20 01:48:02 2022, Koji, Update, BHD, PR2 transmission calculation updated 
Message ID: 16602     Entry time: Thu Jan 20 01:48:02 2022     In reply to: 16598
Author: Koji 
Type: Update 
Category: BHD 
Subject: PR2 transmission calculation updated 

IMC is not such lossy. IMC output is supposed to be ~1W.

The critical coupling condition is G_PRC = 1/T_PRM = 17.7. If we really have L_arm = 50ppm, we will be very close to the critical coupling. Maybe we are OK if we have such condition as our testing time would be much longer in PRMI than PRFPMI at the first phase. If the arm loss turned out to be higher, we'll be saved by falling to undercoupling.
When the PRC is close to the critical coupling (like 50ppm case), we roughly have Tprc x 2 and Tarm to be almost equal. So each beam will have 1/3 of the input power i.e. ~300mW. That's probably too much even for the two OMCs (i.e. 4 DCPDs). That's OK. We can reduce the input power by 3~5.

Quote:

LO Power

LO power when PRFPMI is locked is calculated by assuming 1 W of input power to IMC. IMC is assumed to let pass 10% of the power (L_{\rm IMC}=0.1).

 

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