## 2007/11/18 ## by F. Kawazoe (kawazoe@gravity.mtk.nao.ac.jp), K. Somiya, S. Sato, K. Kokeyama and S. Kawamura ## ## ## Input File for FINESSE ## ## ## History: ## ## 2007/11/14 ## ## LCGT plans to use tuned(zero-detuning) RSE as the optical ## configuration. ## ## The length-sensing design of LCGT is as follows. ## ## The conceprual design is to use the carrier and two sets ## of sidebands, (PM and AM), and to use double mod-demodulation ## for sensing the length for the central part. ## ## This file has been used to study several length sensing designs ## in order to decide what is best for LCGT. Shwon here are four ## candidates at that time in terms of length sensing scheme. ## ## We have selected the design 1-type sensing scheme for LCGT. ## The modulation frequencies are subject to change at present. ## ## Please note that length designs except for that of the FP arms ## shown here are subnect to change as the final modulation frequency design ## are not yet determined. Therefor all lengths shown here are designed only to ## meet some resonance conditions for the sidebands and should not ## be taken as LCGT's real length design. ## ## #----------------------------------------------------------------------------------------------- # Resonant Sideband Extraction Interferometer # cComponents, spaces, and nodes explanation. # dump # --------- # n15 # | # (s2a) # | # n14 # -------- # n13 # | # (s2m) # | # n5 # | / | | # Laser -- n0 (eom1) n1 (EOM2)n2 | n3---(sp)---n4 / n6---(s1m)--n10 | n11---(s1a)--- n12| dump # | / | | # n7 # | # (ss) # | # n8 # --------- # n9 # #----------------------------------------------------------------------------------------------- #### constant ##### ## 299792458 m / s # speed of light ### LASER #### l i1 83.52 0 n0 # Input carrier power 75W , here sideband modulation depth 0.1 for both # PM and AM sidebands is estimated. The modulation depth is subject to change. # In reality Mach-Zehnder interferometer will be used to produce # the sidebands in order to avoid producing sub-sidebands, but at present # MZ part is not included in the configuration shown here in the input file. #################### Length sensing designs ####################### #### Design 1##### #### where PM sidebands all transmit through Michelson part #### towards DP and AM sidebands all reflect from Michelson part. mod eo1 60M 0.1 1 am 0 n0 n1 # AM sidebands mod eo2 10M 0.1 3 pm 0 n1 n2 # PM sidebands #------------------------------------------------------ #### Design 2##### #### where Michelson reflectivity for PM equals the reflectivity of PRM #### (i.e. PRC+SEC is critically coupled for PM sidebands) #### and AM sidebands all reflect from Michelson part. #mod eo1 182M 0.1 1 am 0 n0 n1 # AM sidebands #mod eo2 7M 0.1 3 pm 0 n1 n2 # PM sidebands) #---------------------------------------------------------- #### Design 3##### #### where PM sidebands all transmit through Michelson part #### towards DP and AM sidebands mostly reflect from Michelson part. #### used to be Adv.LIGO's design but changed because the frequency #### of PM=180MHz is too high. #mod eo1 9M 0.1 1 am 0 n0 n1 # AM sidebands #mod eo2 180M 0.1 3 pm 0 n1 n2 # PM sidebands #---------------------------------------------------------- #### Design 4##### #where Michelson reflectivity for PM equals the reflectivity of PRM #### (i.e. PRC+SEC is critically coupled for PM sidebands) #### and AM sidebands mostly reflect from Michelson part. #mod eo1 15M 0.1 1 am 0 n0 n1 # AM sidebands #mod eo2 35M 0.1 3 pm 0 n1 n2 # PM sidebands) ################### Optics parameters ############################# m prm 0.80 0.20 90 n2 n3 # Power Recycling Mirror m sem 0.77 0.23 90 n8 n9 # Signal Extraction Mirror m* m1i 3980 20 90 n10 n11 # Input Test Mass R=0.996% , loss of 20ppm m* m1e 30 20 90 n12 dump # End Test Mass R=0.99995% m* m2i 3980 20 0 n13 n14 # Input Test Mass R=0.996% m* m2e 30 20 0 n15 dump # End Test Mass R=0.99995% bs bs1 0.5 0.5 0 45 n4 n5 n6 n7 # Beam Splitter ################### Length parameters ##################################### ###### note 1: Due to fixed vacuum pipe length, there are some restrictions on ###### length parameters. So far what is known is as follows. ###### sp + s1m = 50m ###### note 2: Cavity length deviation from 3000m is set so that the two sidebands ###### are not resonant in the FP cavity but not anti-resonant either, since ###### this will cause residual 2fmod components to be resonant inside the FP cavities. ###### (distance.m is used to calculate space length.) ######################################################### ### for length-sensing design1 ### ### requirement1: Michelson Asymmetry (one way)= pi/2 for PM = 7.49481145m ### requirement 2: PM is resonant in PRC+SEC and AM is resonant in PRC ### FSR of PRC=20/6M, FSR of SEC = 20/6M meet the requirement2 ### note1: Carrier is resonant inside PRC with a phase flip of pi when it is resonant in FP. ### note2: AM sidebands are resonant inside PRC with a phase flip of pi from reflection from Michelson part. ### note3: PM sidebands are anti-resonant inside SEC, and resonant in PRC --> they are resonant inside PRC+SEC. s sp 20 n3 n4 s ss 20 n7 n8 s s1m 21.221463 n6 n10 s s1a 3006.3 n11 n12 s s2m 28.7162745 n5 n13 s s2a 3006.3 n14 n15 #------------------------------------------------------------------------------- ### for length-sensing design2 ### ### requirement1: PM is resonant in PRC + SEC, critical coupled in PRC+SEC --> dl = 0.82105 ### requirement 2: PM is resonant in PRC and in SEC (length-wise) ### and AM is resonant in PRC ### FSR of PRC=2.8M, FSR of SEC = 1.75M meet the requirement2 ### note1: Carrier is resonant inside PRC with a phase flip of pi when it is resonant in FP. ### note2: AM sidebands are resonant inside PRC with a phase flip of pi from reflection from Michelson part. ### note3: PM sidebands are anti-resonant inside SEC, and resonant in PRC --> they are resonant inside PRC+SEC. #s sp 50 n3 n4 #s ss 82.12062 n7 n8 #s s1m 3.94489 n6 n10 #s s1a 3005 n11 n12 #s s2m 3.12384 n5 n13 #s s2a 3005 n14 n15 #---------------------------------------------------------------------------------- ### for length-sensing design3 ### ### requirement1: Michelson Asymmetry (one way)= pi/2 for PM = 0.4163784m ### requirement 2: PM is resonant in PRC + SEC and AM is resonant in PRC ### FSR of PRC=18M, FSR of SEC = 18M meet the requirement2 ### note1: Carrier is resonant inside PRC with a phase flip of pi when it is resonant in FP. ### note2: PM sidebands are anti-resonant inside SEC, and resonant in PRC --> they are resonant inside PRC+SEC. #s sp 1.2 n3 n4 #s ss 1.2 n7 n8 #s s1m 48.973599 n6 n10 #s s1a 3005.7 n11 n12 #s s2m 48.557220 n5 n13 #s s2a 3005.7 n14 n15 #---------------------------------------------------------------------------------- ### for length-sensing design4 ### ### requirement1: PM is resonant in PRC + SEC, critical coupled in PRC+SEC ### --> Michelson Asymmetry 0.16420981m ### requirement 2: AM is resonant in PRC ### FSR of PRC=10/3M, FSR of SEC = 35/6M meet the requirement2 ### note1: Carrier is resonant inside PRC with a phase flip of pi when it is resonant in FP. ### note2: PM sidebands are anti-resonant inside SEC, and resonant in PRC --> they are resonant inside PRC+SEC. #s sp 30 n3 n4 #s ss 10.72763 n7 n8 #s s1m 15.05097361 n6 n10 #s s1a 3000.7 n11 n12 #s s2m 14.88676379 n5 n13 #s s2a 3000.7 n14 n15 #---------------------------------------------------------------------------------- ##### For demphase.m ##### run1:pd2 detSP 60M 0 10M 0 n2 #SP,dc run1:xaxis detSP phase1 lin 0 180 180 run1:x2axis detSP phase2 lin 0 180 180 run2:fsig siglp prm 0.00001 0 #SP,l+ run2:pd3 detSP 60M 0 10M 0 0.00001 0 n2 run2:xaxis detSP phase1 lin 0 180 180 run2:x2axis detSP phase2 lin 0 180 180 run3:fsig siglm1 m1e 0.00001 0 #SP,l- run3:fsig siglm2 m2e 0.00001 180 run3:fsig siglm3 m1i 0.00001 0 run3:fsig siglm4 m2i 0.00001 180 run3:pd3 detSP 60M 0 10M 0 0.00001 0 n2 run3:xaxis detSP phase1 lin 0 180 180 run3:x2axis detSP phase2 lin 0 180 180 run4:fsig sigls sem 0.00001 0 #SP,ls run4:pd3 detSP 60M 0 10M 0 0.00001 0 n2 run4:xaxis detSP phase1 lin 0 180 180 run4:x2axis detSP phase2 lin 0 180 180 run5:pd2 detAP 60M 0 10M 0 n9 #AP,dc run5:xaxis detAP phase1 lin 0 180 180 run5:x2axis detAP phase2 lin 0 180 180 run6:fsig siglp prm 0.00001 0 #AP,l+ run6:pd3 detAP 60M 0 10M 0 0.00001 0 n9 run6:xaxis detAP phase1 lin 0 180 180 run6:x2axis detAP phase2 lin 0 180 180 run7:fsig siglm1 m1e 0.00001 0 #AP,l- run7:fsig siglm2 m2e 0.00001 180 run7:fsig siglm3 m1i 0.00001 0 run7:fsig siglm4 m2i 0.00001 180 run7:pd3 detAP 60M 0 10M 0 0.00001 0 n9 run7:xaxis detAP phase1 lin 0 180 180 run7:x2axis detAP phase2 lin 0 180 180 run8:fsig sigls sem 0.00001 0 #AP,ls run8:pd3 detAP 60M 0 10M 0 0.00001 0 n9 run8:xaxis detAP phase1 lin 0 180 180 run8:x2axis detAP phase2 lin 0 180 180 run9:pd2 detPO 60M 0 10M 0 n4 #PO,dc run9:xaxis detPO phase1 lin 0 180 180 run9:x2axis detPO phase2 lin 0 180 180 run10:fsig siglp prm 0.00001 0 #PO,l+ run10:pd3 detPO 60M 0 10M 0 0.00001 0 n4 run10:xaxis detPO phase1 lin 0 180 180 run10:x2axis detPO phase2 lin 0 180 180 run11:fsig siglm1 m1e 0.00001 0 #PO,l- run11:fsig siglm2 m2e 0.00001 180 run11:fsig siglm3 m1i 0.00001 0 run11:fsig siglm4 m2i 0.00001 180 run11:pd3 detPO 60M 0 10M 0 0.00001 0 n4 run11:xaxis detPO phase1 lin 0 180 180 run11:x2axis detPO phase2 lin 0 180 180 run12:fsig sigls sem 0.00001 0 #PO,ls run12:pd3 detPO 60M 0 10M 0 0.00001 0 n4 run12:xaxis detPO phase1 lin 0 180 180 run12:x2axis detPO phase2 lin 0 180 180 run13:fsig sigLp1 m1e 0.00001 0 #SP,L+ run13:fsig sigLp2 m2e 0.00001 0 run13:pd2 detSPL 10M 0 0.00001 0 n2 run13:xaxis detSPL phase1 lin 0 0 180 180 run14:fsig sigLm1 m1e 0.00001 0 #AP,L- run14:fsig sigLm2 m2e 0.00001 180 run14:pd2 detAPL 10M 0 0.00001 0 n9 run14:xaxis detAPL phase1 lin 0 0 180 180 yaxis abs ##### Option for Gnuplot ##### gnuterm no #GNUPLOT #set contour #set nosurface #set view 0,0 #set cntrparam levels 20 #END