The bottom pendulum stage of the GEO600 suspensions consist of fused-silica masses connected by fused-silica fibres and form a monolithic suspension. This design minimizes thermal noise from the suspension and the test mass. The Advanced LIGO monolithic pendulum systems were – based on their experience from the GEO600 detector – developed and perfected by GEO collaboration members from the University of Glasgow.
CO2 laser production of fused silica fibers for use in interferometric gravitational wave detector mirror suspensions
Review of Scientific Instruments 82, 011301 (2011)