Uniting micro-optics and integrated optics: a case study on bulk resonators

High quality factor bulk resonators made in different materials have demonstrated outstanding performance in key functionalities that are very challenging to achieve in planar photonics. However, they have made no significant technological impact mainly because of their stability and scalability limitations related to the way they are connected to the outside world using prisms or tapered fibers. Here, we show several demonstrations of efficient coupling of bulk resonators to integrated waveguides using different materials like lithium niobate or polymers. Preliminary results of a universal integrated coupler that can be implemented using silicon photonics are also presented.