Merge branch 'master' of git.ligo.org:IFOsim/aundhaisc

 adding notes files from todays call, forgot to pull ReadMe modifications first...

README.md

@@ -25,6 +25,29 @@ cf <a href="https://dcc.ligo.org/LIGO-T1900587">T1900587</a>
  
 
 ## Issues to address
+### Arm Cavity Finesse
+Increase the arm cavity Finesse, will change the DARM linewidth, but not the CARM linewidth (since the T_PRM will be adjusted inversely so as to keep the interferometer impedance matched for the carrier).
+
+Pros:
+ * Allows for increasing the SRC Finesse, while keeping the overall DARM pole frequency ~400 Hz.
+ * smaller beam size at the BS & ITM
+
+Cons:
+ * Increased coating thermal noise from the ITMs (very small effect)
+ * harder to lock the single arms during testing
+
+
+### Arm Cavity g-factor
+Make the cavity stable.
+
+Pros:
+ * change the Sidles-Sigg effect
+ * change the PI situation
+
+Cons:
+ * Increased coating thermal noise from the TMs
+ * mode-matching to the SRC ?
+
 ### DRMi locking (limited by Arm and SRC finesse)
 The SRC is tricky to lock because it has a low finesse (mode hopping, …). The choice of SRC finesse resulted from the (somewhat arbitrary, see <a href="https://dcc.ligo.org/LIGO-T070303">T070303</a>) choice of a relatively low finesse for the arm cavities, which was designed to aid lock acquisition but may have been overkill.