An initiator assembly that includes an exploding foil initiator, an input charge and a detonation detection switch. The exploding foil initiator has a base, a pair of bridge lands, a bridge element, and a plurality of non-metallic material layers. The bridge lands are coupled to the base. The bridge element is disposed between the bridge lands. The non-metallic material layers form a flyer layer and a barrel. The flyer layer is disposed over the bridge element. The barrel defines a barrel aperture and is disposed over the flyer layer such that the barrel aperture is disposed in-line with the bridge element. The input charge is formed of a secondary explosive, the input charge being disposed in-line with the barrel aperture. The detonation detection switch is mounted to the exploding foil initiator within an area defined by an outer perimeter of the base.