Fast M2 measurement for fiber beams based on modal analysis

Daniel Flamm; Christian Schulze; Robert Brüning; Oliver A Schmidt; Thomas Kaiser; Siegmund Schröter; Michael Duparré

doi:10.1364/AO.51.000987

Fast M2 measurement for fiber beams based on modal analysis

Appl Opt. 2012 Mar 1;51(7):987-93. doi: 10.1364/AO.51.000987.

Authors

Daniel Flamm¹, Christian Schulze, Robert Brüning, Oliver A Schmidt, Thomas Kaiser, Siegmund Schröter, Michael Duparré

Affiliation

¹ Institute of Applied Optics, Friedrich Schiller University Jena, Fröbelstieg 1, D-07743 Jena, Germany. daniel.flamm@uni‐jena.de

PMID: 22410903
DOI: 10.1364/AO.51.000987

Abstract

We report on a fast and experimentally easy technique for measuring the beam propagation ratio M(2) of light guided by optical fibers. A holographic filter enables us to determine amplitudes and phases of the excited fiber eigenmodes. The coherent superposition of modes allows the reconstruction of the optical field. With this information at hand, we are able to simulate the free-space propagation of the beam and to perform a virtual caustic measurement. Associated beam propagation ratios M(2) accurately agree with ISO-standard measurements.