Narrow-linewidth single-stage fiber amplifier with an output power of 15 W at 1064 nm

Abstract

For a study of the European Space Agency ESA, Fraunhofer ILT developed and built single-frequency, linearly polarized, power-stabilized highly-stable fiber amplifiers as elegant breadboard (EBB) with an output power >3 W for the future space-based gravitational wave detector LISA (Laser Interferometer Space Antenna). While the fiber amplifier developed at Fraunhofer ILT has fulfilled most of the optical performance requirements, e.g. the relative intensity noise (RIN) [1][2], we further optimized our setup to investigate the power scaling to expand the number of potential applications. In this paper, we present the power scaling of our optimized breadboard setup of our single-stage Ytterbium-doped fiber amplifier. Our fiber amplifier is seeded by a commercial non-planar ring oscillator (NPRO) with a linewidth <10 kHz at a wavelength of 1064 nm. The fiber amplifier is based on cladding-pumped 10 µm-core Ytterbiumdoped SM-PM fiber, and provides an SBS-free amplification to an output power of more than 15 W while maintaining narrow-linewidth and polarization. Additionally, we investigate the relative intensity noise to analyze the temporal stability of the output power and achieve high power stabilities.