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arXiv · 1408.5953

Ultrafast laser inscription of mid-IR directional couplers for stellar interferometry

Alexander Arriola·Sebabrata Mukherjee·Debaditya Choudhury·Lucas Labadie·Robert R. Thomson
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Abstract

We report the ultrafast laser fabrication and mid-IR characterization (3.39 microns) of four-port evanescent field directional couplers. The couplers were fabricated in a commercial gallium lanthanum sulphide glass substrate using sub-picosecond laser pulses of 1030 nm light. Straight waveguides inscribed using optimal fabrication parameters were found to exhibit propagation losses of 0.8 dB/cm. A series of couplers were inscribed with different interaction lengths, and we demonstrate power splitting ratios of between 8% and 99% for mid-IR light with a wavelength of 3.39 microns. These results clearly demonstrate that ultrafast laser inscription can be used to fabricate high quality evanescent field couplers for future applications in astronomical interferometry.

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Alexander Arriola, Sebabrata Mukherjee, Debaditya Choudhury, Lucas Labadie, Robert R. Thomson. 2014-08-26. Ultrafast laser inscription of mid-IR directional couplers for stellar interferometry. https://doi.org/10.1364/ol.39.004820

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