Recent experiments have demonstrated that squeezed vacuum can be injected into gravitational wave detectors to improve their sensitivity at detection frequencies where they are quantum noise limited.
This technique can be applied to Advanced LIGO provided that some additional design requirements are met. Optomechanical interactions dictate that the vacuum’s squeezed quadrature must rotate by 90 degrees around 50 Hz.
Additionally, improved detector performance requires that backscatter and other technical limitations be mitigated. I will present recent work at MIT towards developing a suitable squeezed light source for Advanced LIGO.