LISA Laser System and European Development Strategy

The Laser Interferometer Space Antenna (LISA), with its extreme distance measurement requirements (pm over arm lengths of 2.5 million km), imposes many stringent requirements on the laser systems used for the distance metrological measurements. In particular, frequency and power stability, sideband phase noise, and frequency reproducibility, the need of manufacturing multiple laser systems and extremely challenging lifetime (extended mission duration of 12.5 years) which demand a streamlined laser design and a particular attention to reliability and procurement strategy, all pose a significant challenge. The main requirements will be presented and analysed. Some preliminary strategies as it pertains to procurement and lot screening shall also be approached. The current configuration and break-down of the future on-board laser systems shall be provided detailing in particular the critical interfaces. Existing space heritage hardware (such as the LISA Pathfinder Master Oscillator) and new specialized developments are under study in both Europe and the US. European industry is developing custom Power Amplifiers to reach the end-of-life requirement of 2W (in Continuous Wave operation). In parallel alterative possible sources for a back-up Master Oscillator are also being investigated, based on off the shelf components and proprietary technologies. An overview of the development strategy shall be presented as well as some details on the specific hardware.