Speaker
Description
For ET-LF, novel silicon-based coatings can be a potential solution to decrease Brownian thermal noise and increase the ET sensitivity. To keep coating absorption at levels comparable to current coatings, operation at an increased laser wavelength, for example to 2090 nm, is required. ETpathfinder aims to perform investigations on IFOs at 2090nm and therefore requires a high-stability laser system. For this, Fraunhofer ILT started with the development of a suitable laser system.
We present our 10 W class CW holmium-doped fiber amplifier operating at a
wavelength of approx. 2090 nm. With our monolithic, single-frequency, all-PM setup, we achieve a polarization extinction ratio of 26 dB, excellent beam quality M2 = 1.18, and no observable ASE for relative power levels of 60 dB.