aLIGO LHO Logbook

H1 SQZ (SQZ)

haocun.yu@LIGO.ORG - posted 14:28, Friday 09 November 2018 - last comment - 09:27, Saturday 10 November 2018(45164)

SQZ Vent Prep - Fiber arrangements & mode match

[Sheila, Terry, Haocun]

Fiber arrangement:

The patch panel with sleeves of CLF and Green path was moved to the left side of the table.
The on-table fiber was changed to 5m ones for both green (Thorlabs P3-460P-FC-5) and CLF (Fabrice).
The temporary fiber arrangement from HAM6 to ISCT6 for green: orignal 6m + new Thorlabs 2m as a shield. This part will be changed to a new 5m Thorlabs P3-460P-FC-5 on Monday together with the new feedthrough.

Feedthrough and Mode Matching Solution:

I double-checked the mode matching for feedthrough SN7 using Fabrice's Measurements.
SN7 Mode: waist radius = 156um @ 0.36m out from fiber coupler. The same solution can be used, reaching an overlap of 98.5%.
SN2 will be a back-up option, which was a prototype.

4 Irises were placed on ISCT6 for alignment references.

Comments related to this report

daniel.sigg@LIGO.ORG - 17:38, Friday 09 November 2018 (45171)

Terry Nutsinee Daniel

The cables for the OSA were routed through a new feedthrough panel. There are no gaps left.

The cleanroom curtains were lowered around ISCT6 and SQZT6.

nutsinee.kijbunchoo@LIGO.ORG - 09:27, Saturday 10 November 2018 (45172)

Some additional information:

100mW is now going to the SHG. Since the temporary EOM set up has been removed we now can use half wave plate as power control again (for green power to fiber coupler).
Current transmission from the pump coupler to end of 5 m fiber on ISCT6 is 71%. Terry plan on working on improving this during the weekend.
About 57% total transmission from ISCT6 table to the end of 2m cable. ~8% total transmission from ISCT6 to SQZT6 (looking at pump refl).
The power coming through was enough to lock the OPO. 5 irises were placed on the SQZT6. 3 for red path (to homodyne), 2 for pump path (to OPO refl).

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