Common-clock very long baseline interferometry using a coherent optical fiber link
Authors: Clivati C., Aiello R., Bianco G., Bortolotti C., De Natale P., Di Sarno V., Maddaloni P., Maccaferri G., Mura A., Negusini M., Levi F., Perini F., Ricci R., Roma M., Amato Santamaria L., Siciliani de Cumis M., Stagni M., Tuozzi A., Calonico D.
Autors Affiliation: Ist Nazl Ric Metrol INRIM, Str Cacce 91, I-10135 Turin, Italy; CNR, INO, Via Campi Flegrei 34, Pozzuoli, Italy; Complesso Univ MS Angelo, Sez Napoli, INFN, Via Cintia, Naples, Italy; ASI, Ctr Geodesia Spaziale G Colombo, CGS, Matera, Italy; INAF, IRA, Ist Radioastron, Via Gobetti 101, Bologna, Italy; ASI, Rome, Italy
Abstract: Among the most powerful techniques for the exploration of the Universe is very long baseline interferometry (VLBI), which is based on the simultaneous observation of radio sources in the sky with arrays of distant ground-based antennas. One of the effects currently limiting its ultimate sensitivity is the phase-instability of the reference clocks adopted at each antenna. This termcan be made negligible delivering the same clock signal to multiple telescope sites using optical fibers. We realized such an infrastructure by disseminating a coherent optical frequency signal to two distant radio telescopes using a 1739-km-long fiber.We performed a 24 h geodetic VLBI campaign in which the same clock reference was used at both telescopes and analyzed it using standard VLBI procedures. The results were consistent with the expectations, confirming that the proposed approach is feasible and configures as a novel tool for studying the role of clocks, troposphere, and systematic effects in the ultimate VLBI resolution.
Volume: 7 (8) Pages from: 1031 to: 1037
More Information: Ministero dell´Istruzione, dell´Universita e della Ricerca (20152MRAKH), (MetGeSp); Agenzia Spaziale Italiana (DTF-Matera); European Metrology Programme for Innovation and Research (EMPIR-17IND14-WRITE), (EMPIR-18SIB06-TIFOON).KeyWords: FREQUENCY; GEODESY; BANDDOI: 10.1364/OPTICA.393356Citations: 31data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2023-06-04References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here