Affiliation:
1. I. Physikalisches Institut der Universität zu Köln
2. Leibniz-Institut für Astrophysik Potsdam (AIP)
3. Center for High Angular Resolution Astronomy, Georgia State University
4. LESIA of Paris Observatory/CNRS/UPMC/Univ. Paris Diderot
Abstract
A fiber-connectorized K-band integrated-optics two-telescope beam combiner was developed for long-baseline interferometry at the CHARA telescope array utilizing the ultrafast laser inscription (ULI) technique. Single-mode waveguide insertion losses were measured to be ∼1.1dB over the 2–2.3 µm window. The development of asymmetric directional couplers enabled the construction of a beam combiner that includes a 50:50 coupler for interferometric combination and two ∼75:25 couplers for photometric calibration. The visibility of the bare beam combiner was measured at 87% and then at 82% after fiber-connectorization by optimizing the input polarization. These results indicate that ULI technique can fabricate efficient fiber-connectorized K-band beam combiners for astronomical purposes.
Funder
Heriot-Watt University
H2020 Future and Emerging Technologies
Horizon 2020 Framework Programme
Science and Technology Facilities Council
Engineering and Physical Sciences Research Council
Deutsche Forschungsgemeinschaft
Subject
Atomic and Molecular Physics, and Optics,Engineering (miscellaneous),Electrical and Electronic Engineering