Femtosecond Laser Direct-Write Integrated Optics Beam Combiner for the Detection of Exoplanets

Nulling interferometry has emerged as a powerful method for exoplanet imaging, offering a solution to the challenges of achieving high contrast and angular resolution faced by individual telescopes. By suppressing starlight while transmitting light from off-axis planets, this technique significantly enhances the ability to detect faint planetary signals. However, to advance its practical implementation, a shift from traditional bulk optics to more compact and scalable solutions is essential. Classical bulk optics have long established their efficacy for on-sky interferometry. In addition to being large and prone to alignment challenges, traditional bulk optics systems are inherently constrained by phase instability and challenging spatial filtering-key factors that limit imaging contrasts. Integrated photonic devices can overcome these limitations by offering a compact, robust, and scalable alternative that benefits from the inherent stability of monolithic fabrication. Nulling interferometry can be performed using tricouplers [1]. The tricoupler comprises of three single mode waveguides which can not only provide an achromatic interferometric suppression of star light but also two phase sensitive bright outputs to provide live feedback to an upstream deformable mirror for fringe tracking.