FRD and scrambling properties of recent non-circular fibres

Gerardo Avila, Ian S. McLean, Suzanne K. Ramsay, Hideki Takami
2012 Ground-based and Airborne Instrumentation for Astronomy IV  
Optical fibres with octagonal, square and rectangular core shapes have been proposed as alternative to the circular fibres to link the telescopes to spectrographs in order to increase the accuracy of radial velocity measurements. Theoretically they offer better scrambling properties than their circular counterparts. First commercial octagonal fibres provided good near field scrambling gains. Unfortunately the far field scrambling did not show important figures. This article shows test results
more » ... new fibres from CeramOptec. The measurements show substantial improvements of the far field scrambling gains. In addition, evaluation of their focal ratio degradation (FRD) shows much better performances than previous fibres.
doi:10.1117/12.927447 fatcat:jsinl2wjenbfblk24er57znm7u