Fringe tracking at longer wavelengths is advantageous for its larger Fried parameter (R₀) and longer coherence time (τ₀). The fringe trackers which are currently available at the VLTi (Finito, FSU, Gravity, etc.) tracks fringes at the near infrared wavelengths (H and K bands). In our work we try to explore the possibilities to track near and mid- infrared fringes using GLS based laser written integrated optics beam combiners. We simulate the atmospheric optical path difference (OPD) using Kolmogorov/Von-Karman atmospheric turbulence statistics. We also include the measured the piston noise generated due to the instrumental vibrations. Using the resulting OPD time series we can estimate the sensitivity of the fringe tracker at the L band.

Date Published: 4 August 2016
PDF: 11 pages
Proc. SPIE 9907, Optical and Infrared Interferometry and Imaging V, 990736 (4 August 2016); doi: 10.1117/12.2232610

Published in SPIE Proceedings Vol. 9907:
Optical and Infrared Interferometry and Imaging V
Fabien Malbet; Michelle J. Creech-Eakman; Peter G. Tuthill, Editor(s)