The investigation of thermal and non-thermal noises in fused silica fibers for Advanced LIGO suspension

The results of experimental investigation of the mechanical noise produced by fused silica fibers at room temperature is reported. The best achieved resolution is about 0.01kT for the modes with quality factor from 105 to 107. Over the 90 hours of observation no excess (additional to Brownian) noise was found in fibers loaded at 4%-50% from breaking stress.