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Lock Acquisition in Resonant Optical Interferometers


Evans, Matthew John (2002) Lock Acquisition in Resonant Optical Interferometers. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/N1J2-M098.


The LIGO (Laser Interferometric Gravitational-wave Observatory) project, and other projects around the world, are currently planning to use long-baseline (> 1 km) interferometers to directly detect gravitational radiation from astrophysical sources. In this work we present a framework for lock acquisition, the process by which an initially uncontrolled resonant interferometer is brought to its operating point. Our approach begins with the identification of a path which takes the detector from the uncontrolled state to the operational state. The properties of the detector's outputs along this path, embodied in the sensing matrix, must be determined and parameterized in terms of measureables. Finally, a control system which can compute the inverse of the sensing matrix, apply it to the incoming signals, and make the resulting signals available for feedback is needed to close the control loop. This formalism was developed and explored extensively in simulation and was subsequently applied to the LIGO interferometers. Results were in agreement with expectation within error, typically ±20% on the sensing matrix elements, and the method proved capable of bringing a high-finesse power-recycled Fabry-Perot-Michelson interferometer (a LIGO detector) to its operating point.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:LIGO ; optical interferometers
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Barish, Barry C.
Thesis Committee:
  • Barish, Barry C. (chair)
  • Libbrecht, Kenneth George
  • Thorne, Kip S.
  • Weinstein, Alan Jay
Defense Date:12 December 2001
Record Number:CaltechETD:etd-12062004-115632
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4806
Deposited By: Imported from ETD-db
Deposited On:08 Dec 2004
Last Modified:05 Nov 2021 20:35

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PDF (Evan_m_2002.pdf) - Final Version
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