Within the European Space Agency (ESA) activity “Gravitational Wave Observatory Metrology Laser” we designed a laser head to fulfill the LISA laser requirements using a non-NPRO seed laser technology: an external cavity diode laser (ECDL) with resonant optical feedback from an external cavity as master oscillator for further linewidth narrowing. Furthermore, our design features a single-stage fiber amplifier with an amplification factor of about 20 dB. This paper covers the requirements on the laser source for LISA, the design and first results of performance characterization of the laser head breadboard.
For studies of the European Space Agency ESA, Fraunhofer ILT develops and builds narrowband, power-stabilized fundamental mode fiber amplifiers especially for future space-based gravitational-wave detectors, e.g. LISA, and for Earth gravity field missions. In this paper, we present the status of our ongoing work, based on a highly stable fiber amplifier designed for a Next Generation Gravity field Mission (NGGM) pre-study, towards power scaling as well as enhancement of the Technology Readiness Level (TRL). Our amplifier has already demonstrated to meet the requirements for future gravity field missions. It features a design that is free of stimulated Brillouin scattering (SBS) and a feedback loop for power stabilization.