Astrophotonic technologies

Over the past two decades, photonics have been developed as technological solutions for astronomical instrumentation for, e.g., near-infrared spectroscopy and long baseline interferometry. With increasing instrument capabilities, large quantities of high precision optical components are required to guide, manipulate, and analyze the light from astronomical sources. Photonic integrated circuits (PICs) and fiber-based devices offer enormous potential for astronomical instrumentation, as they can reduce the amount of bulky free-space optics and pave the way for innovative solutions. Astrophotonic devices are particularly interesting for interferometry due to their compact design on the centimeter scale, even for a large number of telescope inputs. Already, astrophotonic components are integrated in high-end instruments at the VLTI and at the CHARA Array. Photonic beam combiners at wavelengths from visible to mid-infrared have been fabricated using lithographic techniques or ultrafast-laser inscription, with several components tested on-sky. This paper will provide a glimpse into the growing field of astrophotonics, its current status and potential for new technologies.