Diagonalization of Optical Lever signals for Type B suspensions

Document #:

JGW-T1808963-v1

Document type:

T

Submitted by:

Tak Lun Terrence Tsang

Updated by:

Tak Lun Terrence Tsang

Document Created:

04 Sep 2018, 06:25

Contents Revised:

04 Sep 2018, 06:25

DB Info Revised:

04 Sep 2018, 06:29

Abstract:

As a supplement to the student lecture (JGW-G1808874-v1), the diagonalization matrix of the Type-B suspensions optical lever signals is further discussed. In particular, we proposed two ways to decouple any two degrees of freedom, using DC offsets or power spectrum. And, the mathematical expression of the diagonalization matrix was also derived for length and tilt optical lever. One can simply plug parameters like beam path length, an angle of rotational transformation and calibration factor for QPD in order to obtain the numerical matrix that can be input to the MEDM OL2EUL matrix. However, the correction factor for compensating misplacement of the length OpLev hasn't been derived. But, this effect of misplacement should be minimal.

Files in Document:

• Diagonalization_of_Optical_Lever_signals_for_Type_B_su...pdf (401.4 kB)

Topics:

• Activity:KAGRA
• Detector:Suspensions
• Detector:Seismic Isolation

Authors:

• Tak Lun Terrence Tsang

Keywords:

Optical_Lever OpLev Diagonalization Decouple Decoupling Type-B VIS Vibration_Isolation_System