Six-telescope integrated optics beam combiner fabricated using ultrafast laser inscription for J- and H-band astronomy

Abstract

We have built and characterized, to our knowledge, the first six-telescope discrete beam combiner (DBC) for stellar interferometry in the astronomical J-band. It is the DBC with the largest number of beam combinations and was manufactured using ultrafast laser inscription in borosilicate glass, with a throughput of ≈56%. For calibration of the visibility-to-pixel matrix, we use a two-input Michelson interferometer and extract the complex visibility. A visibility amplitude of 1.05 and relative precision of 2.9% and 3.8% are extracted for 1328 nm and 1380 nm, respectively. Broadband (≤40nm) characterization is affected by dispersion but shows similar performance.

Photonic integrated circuits through femtosecond laser waveguide writing in glass

“…This technique typically relies on complex interferometers that are difficult to scale. However, a laboratory-tested DBC manufactured by FLW has already shown the potential to combine signals from six telescopes simultaneously in the J band [14], indicating a likely path toward high-resolution astronomical observations.…”