Passive and active optical microresonators are versatile optical devices and show the potential to become compact building blocks in larger integrated systems performing key optical signal processing functions such as wavelength filtering, switching, regeneration, and buffering. Some of these functions find already widespread use in novel optical sensor arrangements and can be potentially employed in future advanced telecom systems. Various microresonator geometries have been studied recently each with associated unique characteristics. The presentation will cover our recent demonstration of first integrated microsphere laser and fabrication of novel optical microresonators, namely the "microdiscus", the "microbottle", the "microstub" and the "microrod", and their performance. I will also introduce our recent activity and capability at the Mid-IR wavelengths for waveguide-based biomedical sensing.