A Caltech Library Service

Time-Delay Interferometry

Tinto, Massimo and Dhurandhar, Sanjeev V. (2005) Time-Delay Interferometry. Living Reviews in Relativity, 8 . Art. No. 4. ISSN 1433-8351. PMCID PMC5253916. doi:10.12942/lrr-2005-4.

PDF - Published Version
Creative Commons Attribution.


Use this Persistent URL to link to this item:


Equal-arm interferometric 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 detector. In order 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 and mathematical foundations of TDI as it will be implemented by the forthcoming space-based interferometers such as the Laser Interferometer Space Antenna (LISA) mission. We have purposely left out from this first version of our “Living Review” article on TDI all the results of more practical and experimental nature, as well as all the aspects of TDI that the data analysts will need to account for when analyzing the LISA TDI data combinations. Our forthcoming “second edition” of this review paper will include these topics.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Tinto, Massimo0000-0002-8107-5148
Additional Information:© Max Planck Society and the author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Accepted on 16 May 2005; Published on 15 July 2005 S.V.D. acknowledges support from IFCPAR, Delhi, India under which the work was carried out in collaboration with J.-Y. Vinet. This research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
PubMed Central ID:PMC5253916
Record Number:CaltechAUTHORS:TINlrr05
Persistent URL:
Official Citation:Sanjeev V. Dhurandhar and Massimo Tinto, "Time-Delay Interferometry", Living Rev. Relativity 8, (2005), 4. URL (cited on 23 December 2005):
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1146
Deposited By: Archive Administrator
Deposited On:23 Dec 2005
Last Modified:08 Nov 2021 19:07

Repository Staff Only: item control page