Spotlight on "Ultrafast laser inscription of an integrated photonic lantern"

In many applicative fields, fiber-optic devices are bound to be replaced by their integrated counterparts, which offer large benefits in terms of costs, size, robustness, and suitability for mass-production. Indeed, integrated technologies make use of fabrication processes, similar to those that have been employed in electronics for several decades, enabling the realization of many different components and functionalities that can be gathered together on a small photonic chip. However, a strong limitation of conventional integrated optical technologies is that they are inherently planar. This means that only architectures lying on a common photonic layer can be fabricated, whereas structures extending in a full 3D space are not generally allowed. To circumvent this limit, a discrete number of photonic layers can be stacked, as it happens in electronics, even though in integrated optics, vertical connections are much more tricky and only a few guiding layers can be reasonably overlapped.