NPROs as highly reliable laser sources
Since 2000 a team of scientists and engineers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute), at the Laser Zentrum Hannover, and at LIGO have been working on the design, fabrication, and implementation of a 200 W laser system for the second generation Advanced LIGO GWD [8,9]. As NPROs have proven to be reliable, low-noise lasers in the first generation of GWDs, the team again relies on a NPRO master laser (Mephisto2000, Coherent). Even though the Advanced LIGO GWDs will start operation not before 2015, four pre-stabilized 200 W laser systems have been in continuous operation since 2010. Again the NPROs have proven very reliable as documented by the sophisticated digital monitoring system of Advanced LIGO.
At the GEO600 detector NPROs have been in use since 1998: between 1998 and 2011 in a master-slave configuration  and since October 2011 as a seed laser for a 35 W amplifier system . Since the summer of 2010 NPROs serve an additional purpose in the GEO600 GWD: Three of them are used in compact experimental unit that delivers a non-classical state of light (squeezed vacuum) to overcome the shot-noise limit at the GW readout port of GEO600. (More details about the squeezer and its implementation in GEO600 can be found in references  and .) This is another laser application in GWDs that requires low-noise laser sources which the NPROs have been reliably providing for years.
Due to their low-noise performance and high reliability NPRO lasers were successfully operated for many years in all GWDs of the first generation and in many research labs of the GW community. They are the preferred seed-laser source for GWDs of the second generation which is currently been commissioned and they might also be used in third-generation GWDs. They are an excellent choice for precision experiments that require continuous-wave single-mode single-frequency laser sources at 1064 nm.