Characterization of a photonic lantern receiver used on a free space optical link

Abstract

Photonic lanterns are investigated for use in extracting lowest order spatial mode beams from light aberrated after propagation through atmospheric turbulence. Both 1x7 and 1x19 photonic lanterns have been tested and in each case the lantern was at the focus of a 100mm aperture, f/2 lens. The angular throughput of these devices was measured in the laboratory, being placed on a hexapod and centered in a collimated beam from an off-axis parabola. In this way the optimal response of the lantern was established as a function of the angle of the incident beam. The laboratory measurements are useful in comparing the power efficiency between sample lanterns and when comparing with data recorded across the 16km maritime link over the Chesapeake Bay. This study is looking at the feasibility of using the photonic lantern concept as a means of combining the various phase components of a beam aberrated by atmospheric turbulence, enabling a coherent receiver.