Sensing and control problems in low finesse cavities, or "how (not) to hop"

Document #:

LIGO-G1500645-v3

Document type:

G - Presentations (eg Graphics)

Abstract:

During the commissioning of aLIGO, particular challenges have arisen in the length control of two low finesse cavity systems: the ALS control of the 4km arm cavities, and the control of the signal recycling cavity in the H1 dual-recycled Michelson interferometer. Both of these systems have exhibited mode-hopping behaviour which is detrimental to their stability. I will present the results of simulations looking into the causes of mode-hopping in low finesse cavities, and discuss possible mitigation strategies for avoiding the problem in the future.

Files in Document:

• PFulda_GWADW_hopping.pptx (6.7 MB)

Topics:

• Commissioning
• Sensing and Control

Authors:

• Paul Fulda
• Daniel Brown
• Andreas Freise

Related Documents:

• LIGO-T1500230: Simulation investigation of mode hopping in the H1 signal recycling cavity

Associated with Events:

GWADW 2015 held on 17 May 2015 in Girdwood, Alaska