As the second-generation gravitational wave detectors approach their design sensitivity, the first direct detection of gravitational waves will herald the era of gravitational wave astronomy. By “listening into space” in the gravitational wave spectrum we will learn more about the origin and content of the universe than has ever been possible before. To achieve this, however, we need ever improving sensitivity to go beyond advanced detectors, and this calls for innovative ways to combat both technical noise sources and the eventually limiting contributions caused by quantum noise. In this talk I will present recent results and ongoing experiments that offer new ways of dealing with existing technical challenges typical for the field of interferometric gravitational wave detection, and for the wider quantum optics community. I will also introduce novel quantum noise reduction schemes that work towards improving the sensitivity of future generation gravitational wave observatories.