An infrared integrated optic astronomical beam combiner for stellar interferometry at 3-4 microns

TL;DR

This paper reports the design and fabrication of integrated-optic beam combiners operating in the 3-4 micron range for stellar interferometry, demonstrating on-chip fringe scanning and white light fringes in the laboratory.

Contribution

First implementation of integrated-optic combiners in the 3-4 micron L band for astronomical interferometry with on-chip electro-optic fringe scanning.

Findings

Successful fabrication of lithium niobate beam combiners

Demonstration of on-chip fringe scanning

Laboratory production of white light fringes

Abstract

Integrated-optic, astronomical, two-beam and three-beam, interferometric combiners have been designed and fabricated for operation in the L band (3 - 4 microns) for the first time. The devices have been realized in titanium-indiffused, x-cut lithium niobate substrates, and on-chip electro-optic fringe scanning has been demonstrated. White light fringes were produced in the laboratory using the two-beam combiner integrated with an on-chip Y-splitter.