title: Fast M2 measurement for fiber beams based on modal analysis.
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.
authors.affiliation: Institute of Applied Optics, Friedrich Schiller University Jena, Fröbelstieg 1, D-07743 Jena, Germany. daniel.flamm@uni‐jena.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Flamm
authors.forename: Christian
authors.initials: C
authors.lastname: Schulze
authors.forename: Robert
authors.initials: R
authors.lastname: Brüning
authors.forename: Oliver A
authors.initials: OA
authors.lastname: Schmidt
authors.forename: Thomas
authors.initials: T
authors.lastname: Kaiser
authors.forename: Siegmund
authors.initials: S
authors.lastname: Schröter
authors.forename: Michael
authors.initials: M
authors.lastname: Duparré