# Laser

l laser 1 0 n1
 

# Define the modulation sidebands
s s1 0 n1 n2
mod eom1 30M 0.3 3 pm n2 n3 # GEO MC
s s2 0 n3 n5



%%% ring cavity 
 		 		

bs bs1 0.9995 0.00045 0 44.284 n5 n7 n6 n8
bs bs2 0.99994  0.00001 0 1.433  n9 n10 n11 n12 #curved
bs bs3 0.9997  0.00025 0 44.284 n13 n14 n15 n16
		 
s sL1 10.434 n6 n9
s sL2 10.434 n10 n13
s sL3 0.3 n8 n14	 		 		
		 

attr bs2 Rc 37.8


cav c1 bs2 n9 bs2 n10     # Define cavity eigenmode

maxtem 3



################

#fsig sigmby bs2 ybeta 0.0001 0 10n  #pitch Mb
#fsig sigmc bs3 ybeta 0.0001 0 10n # pitch Mc
#fsig sigma bs1 ybeta 0.0001 0 10n # pitch Ma ### Does not work
attr bs3 ybeta 10n


#fsig sigmby bs2 xbeta 0.0001 0 10n  #pitch Mb
#fsig sigmc bs3 xbeta 0.0001 0 10n # pitch Mc
#fsig sigma bs1 xbeta 0.0001 0 10n # pitch Ma ### Does not work
#attr bs3 xbeta 10n

########demodulation phase check
######run3:xaxis QPD1 phase lin -180 180 180 # at 0 it is max, OK.
######run3:put QPD2 phase $x1
######run3:diff bs2 xbeta


# Set up beamsplitter for detection stage

s s3 0 n7 n18
		 		 		  
bs bs5 0.5 0.5 0 45 n18 n19 n20 dump		 # BS to get two beams for two QPD's
s s4 0 n19 n21
s s5 0 n20 n22

attr s3 g 0      	  
attr s4 g 0 		 		  
attr s5 g 90 		 		  

trace 8

# power detectors
#pd pcav n10 # ok, it is resonant 
#pd pref n7

## how about demodulation phase?
#run3:xaxis pref phase lin -180 180 180
#run3:diff bs2 phi
#pd1 pref 30M 0 n21 # should be 0 it seems.


xaxis s3 gx lin 0 90 100
put* s3 gy $x1

### Set up quadrant photodiodes
#pd2 QPD1 30M 0 0.0001 0 n21  # QPD with Gouy phase 0
#pdtype QPD1 y-split
#pdtype QPD1 x-split

pd1 QPD1 30M 0 n21
pdtype QPD1 y-split
#pdtype QPD1 x-split


yaxis lin abs
#gnuterm no
gnuterm windows
multi
pause