A multimode launch system to be connected to an Optical Time-Domain Reflectometer (OTDR) for use in performing at least one OTDR measurement on a multi-fiber array Device Under Test (DUT), the multimode launch system comprising: an optical switch being connectable to the OTDR during use; a launch array device having an end being connectable to the optical switch and another end being connectable to the multi-fiber array DUT during use, the launch array device having a plurality of multimode launch optical fibers each having at least one first guidance parameter being smaller than a corresponding one of at least one second guidance parameter of at least one multimode optical fiber of the optical switch; and a multi-fiber mode conditioner along the launch array device for inducing a preferential attenuation of higher-order optical modes of test light propagated into the multi-fiber array DUT during use.