24 September 2012 A testbed for simultaneous measurement of fiber near and far-field for the evaluation of fiber scrambling properties
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To improve our understanding of fiber scrambling properties a test bed where fiber near-field and far-field can be measured simultaneously is described. A variety of measurements has been conducted with a selection of fibers from different vendors, including state-of-the-art octagonal and hexagonal fibers. After characterization of the test bench with respect to stability and resolution, scrambling measurements have been conducted using LEDs with central wavelengths ranging between 465-635 nm. The dependence on wavelength regarding to photometrical scrambling has been initially demonstrated. Moreover, two mechanical combined fiber cables have been analyzed that were made from octagonal-circular and hexagonal-octagonal fiber sections. In this context an apparatus for focal ratio degradation (FRD) measurements was assembled to compare different shaped fibers and fiber combinations. Finally, all these preliminary investigations will help in choosing a fiber with good radial scrambling performance for the next generation fiber-link of the fiber optic coupled Cassegrain echelle spectrograph FOCES intended to be operated at the 2.0m Fraunhofer Telescope at the Wendelstein Observatory.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tobias Feger, Anna Brucalassi, Frank U. Grupp, Florian Lang-Bardl, Ronald Holzwarth, Ulrich Hopp, Ralf Bender, "A testbed for simultaneous measurement of fiber near and far-field for the evaluation of fiber scrambling properties", Proc. SPIE 8446, Ground-based and Airborne Instrumentation for Astronomy IV, 844692 (24 September 2012); doi: 10.1117/12.925624; https://doi.org/10.1117/12.925624


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