Bremen 2017 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 5: Postersitzung I

EP 5.7: Poster

Tuesday, March 14, 2017, 16:30–18:00, GW2 2.OG

Long Term Stability of a 1 GHz Laser Frequency Comb — •Michael Debus and Philipp Huke — Institut für Astrophysik, Universität Göttingen, Deutschland

One part of the instrumentation plan of the E-ELT is a high resolution spectrograph (HIRES). For the calibration unit of HIRES a laser frequency comb (LFC) may be used. We are investigating the stability of a 1 GHz LFC. The whole setup is referenced to the GPS-frequency attaining a stability of 8· 10⁻¹². One frequency generator is used to stabilize the repetition rate of the LFC, a second one is used to stabilize the offset frequency. Both are GPS-referenced. The stability of the frequency generators and the corresponding electronics is crucial to the overall performance of the LFC. The behavior of the frequency generators was characterized both on and off the GPS-reference as well as the stability of the electronic circuits. It is also important to know the inherent drift of the offset frequency in order to stabilize it over an extended period of time.

We have reached a relative stability of 1.2· 10⁻¹¹ over 6 hours. Currently we are aiming to keep the LFC in lock for at least 12 hours. Additionally we are investigating other parameters like spectral amplitude stability, polarization and the behavior in a fibre coupling.