@inproceedings{e175ba9fd4984628be263dc417c03a74,
title = "K-band integrated optics beam combiners for CHARA fabricated by ultrafast laser inscription",
abstract = "We report the ultrafast laser inscription (ULI) and characterization of 3 dB directional achromatic couplers for K-band between 2 and 2.4 μm. The couplers were fabricated in commercial Infrasil glass using 1030 nm femtosecond laser pulses. Straight waveguides inscribed using optimal fabrication parameters exhibit an average propagation loss of ~1.21 dB over full range of K-band with a single-mode behavior for a length of 17 mm. Directional couplers with different interaction lengths and waveguide widths were fabricated and characterized. We demonstrate that 3 dB achromatic directional couplers for K-band can be fabricated using ULI. These results show that ULI can fabricate highquality couplers for future applications in astronomical interferometry. Our eventual aim is to develop a two-telescope K-band integrated optical beam combiner to replace JouFLU at CHARA.",
keywords = "Astrophotonics, Beam combiner, CHARA, Integrated optics, Long-baseline interferometry, Ultrafast laser inscription",
author = "Pike, {Fraser A.} and Sharma, {Tarun K.} and Aur{\'e}lien Beno{\^i}t and MacLachlan, {David G.} and Dinkelaker, {Aline N.} and Nayak, {Abani S.} and Kalaga Madhav and Roth, {Martin M.} and Lucas Labadie and Ettore Pedretti and {ten Brummelaar}, {Theo A.} and Scott, {Nicholas J.} and {Coud{\'e} Du Foresto}, Vincent and Thomson, {Robert R.}",
note = "Funding Information: This work was funded by the UK Science and Technology Facilities Council (STFC) – STFC grant no. ST/N000625/1, and by the European Union{\textquoteright}s Horizon 2020 research and innovation program under grant no. 730890 (OPTICON – Optical Infrared Coordination Network for Astronomy). FAP acknowledges support via an Engineering and Physical Sciences Research Council (EPSRC) iCASE studentship part funded by Renishaw. Publisher Copyright: {\textcopyright} 2020 SPIE. All rights reserved.; SPIE Astronomical Telescopes + Instrumentation 2020 ; Conference date: 14-12-2020 Through 22-12-2020",
year = "2020",
month = dec,
day = "13",
doi = "10.1117/12.2561663",
language = "English",
isbn = "9781510636798",
series = "Proceedings of SPIE",
publisher = "SPIE",
editor = "Tuthill, {Peter G.} and Antoine Merand and Stephanie Sallum",
booktitle = "Optical and Infrared Interferometry and Imaging VII",
address = "United States",
}