A system comprises a laser configured to produce a laser beam and to be optically coupled to a first end of an optical fiber of a device under test, a phase mask configured to selectively pass one of a plurality of modes and to be optically coupled to a second end of the optical fiber of the device under test, and a detector optically coupled to the phase mask and configured to determine an intensity of the beam received over the optical connection from the phase mask. The system may further comprise a data analyzer connected to the detector and in selective communication with the phase mask, wherein the data analyzer is configured to set the phase mask to selectively pass a fundamental mode, set the phase mask to selectively pass a higher order mode, receive intensity data from the detector, and determine a performance in the form of at least one performance factor for said device under test according to said intensity data.