Abstract
The planned spaceborne gravitational wave detector LISA will allow the detection of gravitational waves at frequencies between 0.1 mHz and 1 Hz. A breadboard model for the metrology system aka the phasemeter was developed in the scope of an ESA technology development project by a collaboration between the Albert Einstein Institute, the Technical University of Denmark and the Danish industry partner Axcon Aps. It in particular provides the electronic readout of the main interferometer phases besides auxiliary functions. These include clock noise transfer, ADC pilot tone correction, inter-satellite ranging and data transfer. Besides in LISA, the phasemeter can also be applied in future satellite geodesy missions. Here we show the planning and advances in the implementation of an optical testbed for the full metrology chain. It is based on an ultra-stable hexagonal optical bench. This bench allows the generation of three unequal heterodyne beatnotes with a zero phase combination, thus providing the possibility to probe the phase readout for non-linearities in an optical three signal test. Additionally, the utilization of three independent phasemeters will allow the testing of the auxiliary functions. Once working, components can individually be replaced with flight-qualified hardware in this setup.
Highlights
In order to detect gravitational waves in the low frequency regime, the planned space mission LISA [1, 2] will utilize inter-satellite heterodyne interferometry to detect distance changes between free-floating test masses [3]
In addition to LISA, the phasemeter could be used in other applications, like geodesy missions [4], or MHz heterodyne interferometry in general
A frequency offset must be applied in the lock. These circumstances lead to the requirements for the phasemeter to operate with the earlier stated precision within the MHz regime for the phase readout and to be able to control the local laser
Summary
In order to detect gravitational waves in the low frequency regime (mHz-Hz), the planned space mission LISA (laser interferometer space antenna) [1, 2] will utilize inter-satellite heterodyne interferometry to detect distance changes between free-floating test masses [3]. These circumstances lead to the requirements for the phasemeter to operate with the earlier stated precision within the MHz regime for the phase readout and to be able to control the local laser. The phasemeter presented in this paper handles the phase readout with a DPLL (digital phase locked loop) [5, 6], which tracks the MHz signal by mixing it with a digital copy.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
