Universität zu Köln

Benoit, Aurelien, Pike, Fraser A., Sharma, Tarun K., MacLachlan, David G., Dinkelaker, Aline N., Nayak, Abani S., Madhav, Kalaga ORCID: 0000-0002-6711-7137, Roth, Martin M., Labadie, Lucas, Pedretti, Ettore, ten Brummelaar, Theo A., Scott, Nic, du Foresto, Vincent Coude and Thomson, Robert R. (2021). Ultrafast laser inscription of asymmetric integrated waveguide 3 dB couplers for astronomical K-band interferometry at the CHARA array. J. Opt. Soc. Am. B-Opt. Phys., 38 (9). S. 2455 - 2465. WASHINGTON: OPTICAL SOC AMER. ISSN 1520-8540

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Abstract

We present the fabrication and characterization of 3 dB asymmetric directional couplers for the astronomical K-band at wavelengths between 2.0 and 2.4 mu m. The couplers were fabricated in commercial Infrasil silica glass using an ultrafast laser operating at 1030 nm. After optimizing the fabrication parameters, the insertion losses of straight single-mode waveguides were measured to be similar to 1.2 +/- 0.5 dB across the full K-band. We investigate the development of asymmetric 3 dB directional couplers by varying the coupler interaction lengths and by varying the width of one of the waveguide cores to detune the propagation constants of the coupled modes. In this manner, we demonstrate that ultrafast laser inscription is capable of fabricating asymmetric 3 dB directional couplers for future applications in K-band stellar interferometry. Finally, we demonstrate that our couplers exhibit an interferometric fringe contrast of >90%. This technology paves the path for the development of a two-telescope K-band integrated optic beam combiner for interferometry to replace the existing beam combiner (MONA) in Jouvence of the Fiber Linked Unit for Recombination (JouFLU) at the Center forHigh Angular Resolution Astronomy (CHARA) telescope array. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Benoit, Aurelien UNSPECIFIED UNSPECIFIED UNSPECIFIED Pike, Fraser A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sharma, Tarun K. UNSPECIFIED UNSPECIFIED UNSPECIFIED MacLachlan, David G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dinkelaker, Aline N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nayak, Abani S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Madhav, Kalaga UNSPECIFIED orcid.org/0000-0002-6711-7137 UNSPECIFIED Roth, Martin M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Labadie, Lucas UNSPECIFIED UNSPECIFIED UNSPECIFIED Pedretti, Ettore UNSPECIFIED UNSPECIFIED UNSPECIFIED ten Brummelaar, Theo A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scott, Nic UNSPECIFIED UNSPECIFIED UNSPECIFIED du Foresto, Vincent Coude UNSPECIFIED UNSPECIFIED UNSPECIFIED Thomson, Robert R. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-600637
DOI:	10.1364/JOSAB.423727
Journal or Publication Title:	J. Opt. Soc. Am. B-Opt. Phys.
Volume:	38
Number:	9
Page Range:	S. 2455 - 2465
Date:	2021
Publisher:	OPTICAL SOC AMER
Place of Publication:	WASHINGTON
ISSN:	1520-8540
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language POTSDAM MULTIAPERTURE SPECTROPHOTOMETER; OPTICS BEAM COMBINER; DIRECTIONAL-COUPLERS; SPECTROGRAPHS; DESIGN; SILICA; PMAS Multiple languages Optics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/60063