Status of the eLISA on table (LOT) electro-optical simulator for space based, long arms interferometers

Grüning, P.; Halloin, Hubert; Prat, P.; Baron, S.; Brossard, J.; Buy, C.; Heinzel, Gerhard; Bykov, Iouri

doi:10.1007/s10686-015-9448-z

Cited by 3 publications

(2 citation statements)

References 32 publications

(47 reference statements)

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“…7, we finally address aspects of TDI of more practical and experimental nature, and provide a list of references where more details about these topics can be found. It is worth mentioning that, as of today, TDI has already gone through several successful experimental tests (de Vine et al 2010;Miller 2010;Spero et al 2011;Mitryk et al 2012;Grüning et al 2015) and it has been endorsed by the LISA project as its baseline technique for achieving its required sensitivity to gravitational radiation (Amaro-Seoane et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Time-delay interferometry

2020

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Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the photo detector. To solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI). This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

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Section: Introductionmentioning

confidence: 99%

Time-delay interferometry

2020

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“…It was used both to test the performance and feasibility of TDI for heterodyne interferometry and to test phasemeter prototypes. LISA-On- Table (LOT) is an electro-optical simulator developed at the laboratoire AstroParticule et Cosmologie (APC) [9,10]. The results show that in the case of two static unequal arms, first-generation TDI cancels the laser frequency noise as expected.…”

Section: Introductionmentioning

confidence: 84%

Effect of filters on the time-delay interferometry residual laser noise for LISA

et al. 2019

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The Laser Interferometer Space Antenna (LISA) is a European Space Agency mission that aims to measure gravitational waves in the millihertz range. Laser frequency noise enters the interferometric measurements and dominates the expected gravitational signals by many orders of magnitude. Time-delay interferometry (TDI) is a technique that reduces this laser noise by synthesizing virtual equal-arm interferometric measurements. Laboratory experiments and numerical simulations have confirmed that this reduction is sufficient to meet the scientific goals of the mission in proof-ofconcept setups. In this paper, we show that the on-board antialiasing filters play an important role in TDI's performance when the flexing of the constellation is accounted for. This coupling was neglected in previous studies. To reach an optimal reduction level, filters with vanishing group delays must be used on board or synthesized off-line. We propose a theoretical model of the residual laser noise including this flexing-filtering coupling. We also use two independent simulators to produce realistic measurement signals and compute the corresponding TDI Michelson variables. We show that our theoretical model agrees with the simulated data with exquisite precision. Using these two complementary approaches, we confirm TDI's ability to reduce laser frequency noise in a more realistic mission setup. The theoretical model provides insight on filter design and implementation.

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