Phase extraction for laser interferometry in space phase readout schemes and optical testing

authored by: Thomas S Schwarze
supervised by: Karsten Danzmann
Abstract: This thesis was carried out in the area of gravitational physics, specifically in the fields of gravitational wave astronomy and gravimetry. Both fields do or will make use of satellite missions. The planned gravitational wave observatory Laser Interferometer Space Antenna (LISA) aims to detect gravitational waves in the mHz range while missions like the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) measured or will measure, respectively, the Earth’s gravity field to obtain valuable information on hydrology and climate dynamics. The first part of this thesis deals with the heterodyne interferometric readout for LISA and, in particular, its phase extraction system or phasemeter. A summary of the basic principles is followed by a statement of the requirements for the latter. These concern in particular the phase noise contribution, dynamic range and bandwidth. Subsequently, possible testing schemes are being discussed. One experimentally investigated in the scope of this thesis is an optical three-signal test which provides the ability to probe for phasemeter linearity. It utilizes an interferometer of hexagonal footprint, thus called Hexagon, to probe an elegant breadboard model of the LISA phasemeter developed prior to this thesis. An extensive noise hunt was performed to reduce testbed noise. This, in turn, allowed for a measurement in accordance with the single channel LISA requirement extrapolated to three signals (10.23µrad/ √ Hz down to 4mHz). It was conducted with heterodyne frequencies of 3–5.8MHz and a dynamic range of six orders of magnitude. A measurement with full LISA-like values for these parameters did meet the targeted performance outside the Fourier frequency range 0.4–20mHz, inside of which the utilized photoreceivers were limiting. The second thesis part describes the development and implementation of two phase readout schemes for the interferometry technique Deep Frequency Modulation Interferometry (DFMI). The latter aims to provide high scalability and dynamic range in order to interferometrically track test masses in future gravimetry missions or other applications. Two phase extraction methods were investigated, one based on a spectral analysis followed by a non-linear fit, the other on an extended Kalman filter in conjunction with empiric state space modeling. First tests included proof-of-principle tracking of moving mirrors as well as demonstrated a performance of 4µrad/ √ Hz at 0.1–1Hz.
Organisation(s): QUEST-Leibniz Research School
Type: Doctoral thesis
No. of pages: 196
Publication date: 2018
Publication status: Published
Electronic version(s): https://doi.org/10.15488/4233 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@phdthesis{e682e122f4f240fbac2485fbc241c047,
title = "Phase extraction for laser interferometry in space phase readout schemes and optical testing",
abstract = "This thesis was carried out in the area of gravitational physics, specifically in the fields of gravitational wave astronomy and gravimetry. Both fields do or will make use of satellite missions. The planned gravitational wave observatory Laser Interferometer Space Antenna (LISA) aims to detect gravitational waves in the mHz range while missions like the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) measured or will measure, respectively, the Earth{\textquoteright}s gravity field to obtain valuable information on hydrology and climate dynamics. The first part of this thesis deals with the heterodyne interferometric readout for LISA and, in particular, its phase extraction system or phasemeter. A summary of the basic principles is followed by a statement of the requirements for the latter. These concern in particular the phase noise contribution, dynamic range and bandwidth. Subsequently, possible testing schemes are being discussed. One experimentally investigated in the scope of this thesis is an optical three-signal test which provides the ability to probe for phasemeter linearity. It utilizes an interferometer of hexagonal footprint, thus called Hexagon, to probe an elegant breadboard model of the LISA phasemeter developed prior to this thesis. An extensive noise hunt was performed to reduce testbed noise. This, in turn, allowed for a measurement in accordance with the single channel LISA requirement extrapolated to three signals (10.23µrad/ √ Hz down to 4mHz). It was conducted with heterodyne frequencies of 3–5.8MHz and a dynamic range of six orders of magnitude. A measurement with full LISA-like values for these parameters did meet the targeted performance outside the Fourier frequency range 0.4–20mHz, inside of which the utilized photoreceivers were limiting. The second thesis part describes the development and implementation of two phase readout schemes for the interferometry technique Deep Frequency Modulation Interferometry (DFMI). The latter aims to provide high scalability and dynamic range in order to interferometrically track test masses in future gravimetry missions or other applications. Two phase extraction methods were investigated, one based on a spectral analysis followed by a non-linear fit, the other on an extended Kalman filter in conjunction with empiric state space modeling. First tests included proof-of-principle tracking of moving mirrors as well as demonstrated a performance of 4µrad/ √ Hz at 0.1–1Hz. ",
author = "Schwarze, {Thomas S}",
note = "Doctoral thesis",
year = "2018",
doi = "10.15488/4233",
language = "English",
publisher = "Leibniz Universit{\"a}t Hannover",
school = "Leibniz University Hannover",
}