Series production of next-generation guide-star lasers at TOPTICA and MPBC

Martin Enderlein; Axel Friedenauer; Robin Schwerdt; Paul Rehme; Daoping Wei; Vladimir Karpov; Bernhard Ernstberger; Patrick Leisching; Wallace R. L. Clements; Wilhelm G. Kaenders

doi:10.1117/12.2055059

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21 July 2014 Series production of next-generation guide-star lasers at TOPTICA and MPBC

Martin Enderlein, Axel Friedenauer, Robin Schwerdt, Paul Rehme, Daoping Wei, Vladimir Karpov, Bernhard Ernstberger, Patrick Leisching, Wallace R. L. Clements, Wilhelm G. Kaenders

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Proceedings Volume 9148, Adaptive Optics Systems IV; 914807 (2014) https://doi.org/10.1117/12.2055059
Event: SPIE Astronomical Telescopes + Instrumentation, 2014, Montréal, Quebec, Canada

Abstract

Large telescopes equipped with adaptive optics require high power 589-nm continuous-wave sources with emission linewidths of ~5 MHz. These guide-star lasers should be highly reliable and simple to operate and maintain for many years at the top of a mountain facility. After delivery of the first 20-W systems to our lead customer ESO, TOPTICA and MPBC have begun series production of next-generation sodium guide-star lasers. The chosen approach is based on ESO’s patented narrow-band Raman fiber amplifier (RFA) technology [1]. A master oscillator signal from a TOPTICA 50-mW, 1178-nm diode laser, with stabilized emission frequency and linewidth of ~ 1 MHz, is amplified in an MPBC polarization-maintaining (PM) RFA pumped by a high-power 1120-nm PM fiber laser. With efficient stimulated Brillouin scattering suppression, an unprecedented 40 W of narrow-band RFA output has been obtained. This is spatially mode-matched into a patented resonant-cavity frequency doubler providing also the repumper light [2]. With a diffraction-limited output beam and doubling efficiencies < 80%, all ESO design goals have been easily fulfilled. Together with a wall-plug efficiency of < 3%, including all system controls, and a cooling liquid flow of only 5 l/min, the modular, turn-key, maintenance-free and compact system design allows a direct integration with a launch telescope. With these fiber-based guide star lasers, TOPTICA for the first time offers a fully engineered, off-the-shelf guide star laser system for ground-based optical telescopes. Here we present a comparison of test results of the first batch of laser systems, demonstrating the reproducibility of excellent optical characteristics.

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Martin Enderlein, Axel Friedenauer, Robin Schwerdt, Paul Rehme, Daoping Wei, Vladimir Karpov, Bernhard Ernstberger, Patrick Leisching, Wallace R. L. Clements, and Wilhelm G. Kaenders "Series production of next-generation guide-star lasers at TOPTICA and MPBC", Proc. SPIE 9148, Adaptive Optics Systems IV, 914807 (21 July 2014); https://doi.org/10.1117/12.2055059

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