Contribution to the improvement of the correlation filter method for modal analysis with a spatial light modulator

Abstract

Abstract Modal decomposition of light is essential to study propagation properties of waveguides and photonic devices. Modal analysis can be carried out by implementing a computer generated hologram acting as a match filter in a spatial light modulator. In this work, a series of aspects to be taken into account in order to get the most out of this method are presented, aiming to provide operational procedures. First of all, the influence of the mode normalization in the complex amplitude encoding inherent noise is investigated. Then, a method for filter size adjustment based on the LP-modes symmetry is presented. Finally, a robust method to measure the phase difference between modes is proposed. These procedures are tested by wavefront reconstruction in a conventional few mode fiber.