Deep nulling of laser light with a single-mode-fiber beam combiner

The detection of faint companions to bright stars requires the development of very-high-contrast-ratio detection techniques such as nulling interferometry. Here we present, to our knowledge, the first experimental test of a novel beam-combination method, which is based on coupling the light at the center of a dual-aperture interference pattern into a single-mode fiber. Using such a "fiber nuller" approach, a visible He-Ne laser has been stably nulled to as low as 1.3×10^-6, thus validating the approach.