A stable and inexpensive wavelength reference for precise wavelength calibration of radial velocity spectrographs

Tobias Feger*, Michael J. Ireland, Joao Bento, Carlos Bacigalupo

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

    3 Citations (Scopus)


    We present a stable, inexpensive wavelength reference, based on a white-light interferometer for the use on current and future (arrays of) diffraction-limited radial velocity (RV) spectrographs. The primary aim of using an interferometer is to obtain a dense sinusoidal wavelength reference with spectral coverage between 450-650 nm. Its basic setup consists of an unbalanced fiber Mach-Zehnder interferometer (FMZI) that creates an interference pattern in the spectral domain due to superposition of phase delayed light, set by a fixed optical path-length difference (OPD). To achieve long-term stability, the interferometer is actively locked to a stable atomic line. The system operates in closed-loop using a thermo-optic modulator as the phase feedback component. We conducted stability measurements by superimposing the wavelength reference with thorium-argon (ThAr) emission lines and found the differential RMS shift to be ∼5 m s-1 within 30 minute bins in an experiment lasting 5 hours.

    Original languageEnglish
    Title of host publicationGround-based and airborne instrumentation for astronomy V
    EditorsSuzanne K. Ramsay, Ian S. McLean, Hideki Takami
    Place of PublicationWashington, DC
    Number of pages9
    ISBN (Electronic)9780819496157
    Publication statusPublished - 2014
    EventGround-Based and Airborne Instrumentation for Astronomy V - Montreal, Canada
    Duration: 22 Jun 201426 Jun 2014

    Publication series

    NameProceedings of SPIE
    ISSN (Print)0277-786X


    OtherGround-Based and Airborne Instrumentation for Astronomy V


    • wavelength scale referenc
    • phase locking
    • radial velocity
    • fiber Mach-Zehnder interferometer


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