We have experimentally studied the degradation of mode purity for light beams carrying orbital angular momentum (OAM) propagating through simulated atmospheric turbulence. The turbulence is modeled as a randomly varying phase aberration, which obeys statistics postulated by Kolmogorov turbulence theory. We introduce this simulated turbulence through the use of a phase-only spatial light modulator. Once the turbulence is introduced, the degradation in mode quality results in cross-talk between OAM modes. We study this cross-talk in OAM for eleven modes, showing that turbulence uniformly degrades the purity of all the modes within this range, irrespective of mode number.
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